d10t (rjg) service training

SERV1800March 2005

TECHNICAL PRESENTATION

D10T TRACK-TYPE TRACTOR

Service Training Meeting Guide(STMG)

SERVICE TRAINING

D10T TRACK-TYPE TRACTORMEETING GUIDE 800 SLIDES AND SCRIPT

AUDIENCELevel II Service personnel who have knowledge of the principles of machine systems operation,diagnostic equipment, and procedures for testing and adjusting machine systems andcomponents.

CONTENTThis presentation discusses the operation of the power train, the steering system, the implementhydraulic system, the demand fan system, the cooling system, and the Caterpillar Monitoringand Display System with Advisor™ on the D10T Track-type Tractor. Also discussed is theoperation of the controls in the operator compartment and the location and identification of themajor components of the C27 ACERT™ technology engine.

OBJECTIVESAfter learning the information in this presentation, the serviceman will be able to:

1. locate and identify all of the major D10T machine components;2. locate and identify all filters, dipsticks, indicators, fill tubes, drains and test points;3. locate and identify the major components of the C27 ACERT™ technology engine;4. trace the flow of fuel through the C27 engine fuel delivery system;5. trace the flow of air through the C27 engine air intake system;6. trace the flow of coolant through the cooling system of the D10T;7. identify and explain the function/operation of each major component in the hydraulic

demand fan system;8. trace the flow of oil through the hydraulic demand fan system and explain its operation;9. identify and explain the function/operation of each major component in the power train

system;10. trace the flow of oil through the power train hydraulic system and explain its operation;11. explain the function/operation of each major component in the implement hydraulic

system;12. trace the flow of oil through the implement hydraulic system and explain its operation; 13. locate and identify all of the major components in the Caterpillar Monitoring and Display

System, with Advisor™; and14. explain the function of each component in the Caterpillar Monitoring and Display

System, with Advisor™ and explain the system's basic operation at machine start-up.

REFERENCESEngine Specifications (C27 Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .SENR9936Engine Systems Operation, Testing & Adjusting (C27 Engine) . . . . . . . . . . . . . . . . . .SENR9937Engine Troubleshooting Guide (C27 Engine) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .SENR5090Systems Operation, Testing & Adjusting (Power Train) . . . . . . . . . . . . . . . . . . . . . . .RENR7547Systems Operation, Testing & Adjusting (Hydraulic System) . . . . . . . . . . . . . . . . . . .RENR7545Systems Operation (Cooling Systems) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .RENR8198Operation and Maintenance Manual (OMM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .SEBU7764Schematic (Hydraulic System) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .RENR7546Schematic (Power Train Oil System) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .RENR8168Schematic (Electrical) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .RENR8164

PREREQUISITESInteractive Video Course "Fundamentals of Mobile Hydraulics" . . . . . . . . . . . . . . . .TEMV9001Interactive Video Course "Fundamentals of Electrical Systems" . . . . . . . . . . . . . . . .TEMV9002STMG 546 "Graphic Fluid Power Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .SERV1546

SUPPLEMENTARY TRAINING MATERIALS"D10T Track-type Tractor - New Product Introduction" (NPI) . . . . . . .SERV7105-02 (V02N01)STMG 790 "Caterpillar Monitoring and Display System, with Advisor" . . . . . . . . . . .SERV1790STMG 758 "D10R Track-type Tractor" . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .SERV1758Technical Instruction Module "Air Conditioning Principles and Operation" . . . . . . . .SERV2580Technical Instruction Module "Air Conditioning Service Procedures" . . . . . . . . . . . . .SERV2581

Estimated Time: 8 HoursVisuals: 148 SlidesHandouts: 9Form: SERV1800Date: 03/05

© 2005 Caterpillar Inc.

STMG 800 - 3 - Text Reference03/05

TABLE OF CONTENTS

INTRODUCTION ........................................................................................................................5

OPERATOR'S COMPARTMENT................................................................................................6

CATERPILLAR MONITORING AND DISPLAY SYSTEM WITH ADVISOR™ .................22Start-up..................................................................................................................................29

ENGINE......................................................................................................................................34Fuel Delivery System............................................................................................................62Engine Air System ................................................................................................................64Cooling System.....................................................................................................................66Hydraulic Demand Fan System ............................................................................................70Remote Air To Air AfterCooler System ...............................................................................83

POWER TRAIN .........................................................................................................................88Power Train Electronic Control System ...............................................................................89Power Train Hydraulic System.............................................................................................90Torque Divider ....................................................................................................................101Power Shift Transmission ...................................................................................................108Electronic Steering and Brake Control Valve .....................................................................116

IMPLEMENT HYDRAULIC SYSTEM..................................................................................133Implement Hydraulic System Component Identification ...................................................135Pilot Hydraulic System .......................................................................................................145Dozer Control Valve ...........................................................................................................152Dozer Lift and Tilt Circuits.................................................................................................155Ripper Control Valve ..........................................................................................................163Ripper Lift and Tip Circuits................................................................................................165Dual Tilt Operation .............................................................................................................169Quick-drop Valve Operation ...............................................................................................175AutoCarry ...........................................................................................................................181

ELECTRICAL SYSTEM .........................................................................................................187

CONCLUSION.........................................................................................................................191

HYDRAULIC SCHEMATIC COLOR CODE.........................................................................192

VISUAL LIST ..........................................................................................................................193

SERVICEMAN'S HANDOUTS...............................................................................................195Posttest (5 pages) ................................................................................................................199Instructor's Answer Sheets (for Posttest) ............................................................................204


INTRODUCTION

This presentation discusses the major design features and changes, the component location andidentification, and the systems operation of the D10T Track-type Tractor.

The D10T is similar in appearance to the D10R. The operator station incorporates the commoncab, which is also used for the D8T and the D9T Track-type Tractors.

The D10T is powered by the C27 ACERT™ (Advanced Combustion Emissions ReductionTechnology) electronic engine, which is equipped with a Mechanical Electronic Unit Injection(MEUI) fuel system. This engine also utilizes the A4 Electronic Control Module (ECM) enginecontrol and is equipped with a Remote Air To Air AfterCooler (RATAAC) intake air coolingsystem. The C27 engine is a 12-cylinder "V" arrangement with a displacement of 27 liters. TheC27 is rated at 432 kW (580 horsepower) at 1800 rpm.

Other standard features include a power train hydraulic system using the common top pressurestrategy for operation of the transmission and brakes, an electro-hydraulic demand fan, anelectro-hydraulic implement system, the Advanced MOdular Cooling System (AMOCS)radiator, and the new Caterpillar Monitoring and Display System with Advisor™.

The D10T can also be equipped with optional attachments such as an engine pre-lubricationsystem, a cold weather arrangement, a reversing fan and/or fan bypass arrangement, dual tiltblade control with the Automatic Blade Assist (ABA) feature, and AutoCarry. The D10T can beordered ready to accept the Computer Aided Earthmoving System (CAES).

The serial number prefix for the D10T is RJG.

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D10T TRACK-TYPE TRACTD10T TRACK-TYPE TRACTOROR

© 2005 Caterpillar Inc.© 2005 Caterpillar Inc.

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OPERATOR'S COMPARTMENT

The operator's compartment for the D10T incorporates the "Common Cab" design, which isused on the D8T, the D9T, and the D10T Track-type Tractors. The cab is eight inches widerthan the cab used for previous Track-type Tractor models. The cab has wider doors that open20° further for easier entry and exit. It contains more glass area which allows better overallvisibility for the operator.

The new cab design also includes:

- the Caterpillar Monitoring and Display System with Advisor;

- a new dash with an automotive style instrument cluster; and

- a new right-hand console with redesigned controls for lighting and other machine systems.


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The padded left armrest is adjustable fore and aft using the mechanical sliding lever (1). Pullingthe sliding lever up allows the armrest to be moved to the desired position. Releasing the slidinglever mechanically locks the armrest into position.

Power height adjustment of the arm rest is controlled using the rocker switch (2). Depressingand holding the top of the rocker switch raises the armrest height. Depressing and holding thebottom of the rocker switch lowers the armrest height.

The left and right Finger Tip Control (FTC) steering levers (4) are each connected to a rotaryposition sensor (3), which send a PWM signal to the Power Train ECM when they are pulledrearward. The PWM signals are proportional to the movement of the steering levers.

The status of the steering lever position sensors (percent of duty cycle/percent of lever position)may be viewed through the Advisor panel (Service/System Status/Steering screens) or by usingCaterpillar ®Electronic Technician (Cat ET).


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The Finger Tip Control (FTC) console is located at the front of the left armrest. The two smalllevers allow the operator to control left and right turns. A PWM signal is sent to the PowerTrain ECM when the levers are pulled rearward. The Power Train ECM then sends a signal tothe electronic steering clutch and brake control valve, which controls the hydraulic circuits forthe left and right steering clutch and brake pistons. Pulling the left steering lever (1) toward therear of machine (approximately one-half the full travel distance) releases the left steering clutch,which disengages power to the left track. This action will result in a gradual left turn. Pullingthe left steering lever (1) the full travel distance engages the left brake. This action will result ina sharp left turn. The steering response is directly proportional to the amount of steering levermovement. The right steering lever (2) operates the same as the left steering lever.

The tractor direction is controlled by rotating the F-N-R direction lever (3). Pushing on the topof the lever selects the FORWARD direction. Pushing on the bottom of the lever selects theREVERSE direction. The center position of the lever selects NEUTRAL. Each lever position isidentified with a corresponding detent that holds the lever in place.

Depressing the top yellow button (4) upshifts the transmission one gear range at a time.Depressing the bottom yellow button (5) downshifts the transmission one gear range at a time.


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The parking brake switch (5) shifts the transmission to FIRST gear NEUTRAL and energizesthe parking brake solenoid and the secondary brake solenoid (as a backup measure) on theelectronic steering clutch and brake valve, which fully engages the brakes.

The status of the F-N-R direction lever position sensor (percent of duty cycle/percent of leverposition), the transmission upshift and downshift switches, and the parking brake switch may beviewed through the Advisor panel (Service/System Status/Powertrain screens) or by using CatET.

NOTE: When the parking brake is engaged, the secondary brake solenoid is alsoenergized, as a backup measure.


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The right console contains the implement controls and most of the controls and switches formachine systems and functions. The dozer control lever (1) allows the operator to control all ofthe blade functions with one lever.

If the machine is equipped with a ripper, the ripper control handle (2) is located to the rear of thedozer control lever. The ripper control handle allows the operator to control all of the ripperfunctions.

Located to the rear of the ripper handle and on the vertical panel of the right console is the rearaction lamp (3), which alerts the operator of a machine system that is operating out of its normalrange. Forward of the action lamp is a 12-volt, switched power adapter (4).

To the right of the dozer control lever is the horn button (5).

The key start switch (6) is located on the vertical panel above the horn button.

The Cat Advisor™ graphical display module (7) is located forward of the dozer control lever.Cat Advisor will be discussed later in this presentation.


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The dozer control lever (1) allows the operator to control all of the blade functions with onelever. When the lever is moved FORWARD, the blade will LOWER. Moving the lever forwardto a point within 3°- 4° of the soft FLOAT detent causes the quick-drop valve to activate.Moving the lever completely forward to the soft FLOAT detent activates the FLOAT function.The lever can be returned to the centered position and maintain the FLOAT function. Movingthe lever either forward or rearward from the centered position will deactivate the FLOATfunction. Moving the lever to the rear of the center (HOLD) position causes the blade toRAISE. Moving the dozer control lever to the right tilts the right side of the blade down.Moving the lever to the left tilts the left side of the blade down. The FLOAT function may bedisabled through Advisor, using the "Implement Setup" option from the "Settings" menu.

If the machine is equipped with dual tilt, moving the thumb lever (2) to the right allows theoperator to DUMP the blade (PITCH FORWARD). Moving the thumb lever to the left willRACK BACK the blade.

The left yellow button (3) allows the operator to activate sequential segments in the Auto BladeAssist (ABA) cycle and/or the AutoCarry cycle, if equipped with ABA or AutoCarry. The ABAand/or AutoCarry modes must be armed for this button to perform this function.


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The right yellow button (4) cancels the ABA or AutoCarry cycle. The blade may be controlledmanually at any time during the ABA or AutoCarry cycles.

The trigger switch (not visible) is located on the front of the dozer control lever. The triggerswitch toggles between single tilt and dual tilt modes when it is depressed and held. Releasingthe trigger switch toggles back to the default tilt mode. Either single tilt or dual tilt may be setas the default tilt mode using Cat Advisor.

The left rocker switch (5) on the panel ahead of the dozer control lever, and below the Advisorpanel, is the ABA switch. It is used to arm the ABA mode. All of the Auto Blade Pitch settingsfor LOAD, CARRY, and SPREAD may be configured using Cat Advisor.

The right rocker switch (6) manually activates the fan reversing cycle, if the machine isequipped with a reversing fan. (The manual fan reversing switch is not installed in illustrationNo. 6.)

The status of the ABA switch may be viewed through the Advisor panel (Service/SystemStatus/Implement screens) or by using Cat ET.

The status of the manual fan reversing switch may be viewed through the Advisor panel(Service/System Status/Engine screens) or by using Cat ET.

The status of all of the switches and the status of the position sensors (percent of dutycycle/percent of lever position) used on the dozer control lever may be viewed through theAdvisor panel (Service/System Status/Implement screens) or by using Cat ET.

NOTE: There are three different dozer control levers that may be installed in the D10T,depending on how the machine is equipped.

The dozer control lever shown in illustration No. 6 is used on machines that areequipped with dual tilt. Machines equipped with dual tilt also include the ABA feature.

If the machine is not equipped with dual tilt, but is equipped with AutoCarry, the controllever will look the same, but the thumb rocker switch is not active.

If the machine has neither dual tilt nor AutoCarry (standard single tilt machine), thedozer control lever will not include the thumb rocker switch or the two yellow modebuttons. The trigger switch is also not included with the standard single tilt machine.


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The ripper control handle (1) is located to the rear of the dozer control lever. It is similar to theripper control handle that is used on the D10R Track-type Tractor. Pulling back on the left sideof the finger switch (2) moves the tip of the ripper SHANK IN. Pulling back on the right side ofthe finger switch moves the tip of the ripper SHANK OUT.

At the left of the ripper control handle is the thumb switch (3), which controls RIPPER RAISEand RIPPER LOWER. Pushing against the top of the thumb switch RAISES the ripper.Pushing against the bottom of the thumb switch LOWERS the ripper.

Pushing the Auto-Stow button (4) raises the ripper to the maximum height and can move theripper tip to the full SHANK IN or full SHANK OUT position, depending on the operator'ssettings that can be configured using Cat Advisor. There are three Auto-Stow positions that maybe configured. The three positions are: RIPPER RAISE, RIPPER RAISE/SHANK IN, orRIPPER RAISE/SHANK OUT.

The status of the AutoStow switch and the status of the position sensors used on the rippercontrol handle (percent of duty cycle/percent of lever position) may be viewed through theAdvisor panel (Service/System Status/Implement screens) or by using Cat ET.


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The panel on the outside of the right console contains a number of switches that control variousmachine functions. To the immediate right of the key start switch is the High/Low Idle switch (1).

Just above the High/Low Idle switch is the Implement Lockout switch (2), which disablesimplement movement and illuminates the Implement Lockout indicator light in the instrumentcluster when activated. Activating the Implement Lockout switch de-energizes the implementlockout solenoid which shuts off the flow of pilot oil to the implement control valves. Theimplements cannot move with no pilot oil available to the implement control valves.

The AutoShift mode switch (3) activates the AutoShift mode. The AutoShift mode may beconfigured using Cat Advisor, or by using Cat ET.

The Auto KickDown mode switch (4) enables the Auto KickDown mode, when activated.Shift-point sensitivity for the Auto KickDown mode (Low, Medium, and High) may beconfigured using Cat Advisor, or by using Cat ET.


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If the machine is equipped with AutoCarry, the AutoCarry mode switch (5) arms the AutoCarrymode when activated. Blade pitch angles for the LOAD and CARRY segments of theAutoCarry cycle may be configured using Cat Advisor.

The ripper pin puller switch (6) is used to automatically retract and extend the ripper shank pin,if the machine is equipped with a single shank ripper.

The four switches (7) at the rear of the console activate all the exterior machine lights.

The status of the High/Low Idle switch may be viewed through the Advisor panel(Service/System Status/Engine screens) or by using Cat ET.

The status of the AutoShift mode switch and the Auto KickDown mode switch may be viewedthrough the Advisor panel (Service/System Status/Powertrain screens) or by using Cat ET.

The status of the Implement Lockout switch and the AutoCarry mode switch may be viewedthrough the Advisor panel (Service/System Status/Implement screens) or by using Cat ET.


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The main fuse panel, the circuit breakers, and the diagnostic connector are located at the bottomof the left console, inside the left cab door. Opening the hinged door gains access to:

1. the air conditioning remote condenser circuit breaker (if equipped - not shown, above)2. the HVAC blower motor circuit breaker3. the diagnostic connector for the Cat ET4. the 12 volt switched power supply (for powering a laptop computer or other devices)5. the 175 amp alternator fuse6. the main electrical fuse panel, using automotive type fuses

A fuse and breaker identification chart (7) is affixed to the inside of the hinged door. The chartidentifies fuse locations and their associated electrical circuits.

Several spare fuses, a spare 175 amp alternator fuse, and a fuse puller tool are also stored insidethe hinged door.

NOTE: The hinge on the panel door is spring loaded and the door may be easilyremoved, if necessary.


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The HVAC controls and the wiper/washer controls are located overhead, above the rightconsole. From left to right, these controls are:

1. HVAC blower fan speed switch, with four fan speed positions

2. HVAC temperature control

3. air-conditioning selector switch (ON/OFF)

4. front windshield wiper/washer control switch

5. left cab door wiper/washer control switch

6. right cab door wiper/washer control switch

7. rear cab window wiper/washer control switch

The wiper/washer control switches allow for intermittent wiper settings and for high/low speedsettings.


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The dash in the new cab contains a sealed instrument cluster, which replaces the quad gaugemodule, the speedometer/tachometer module, and the Vital Information Display System (VIDS)message center module used in the D10R Track-type Tractor. The instrument cluster is a sealedunit that contains the following four analog gauges:

1. hydraulic oil temperature gauge2. engine coolant temperature gauge3. torque converter oil temperature gauge4. fuel level gauge

The instrument cluster also contains the tachometer (5) and up to fifteen indicator lights thatalert the operator of different operational modes or conditions.The LCD display (6) is positioned below the tachometer. It displays the service hours at thebottom of the display, the track speed at the upper left, and the selected transmission gear anddirection at the upper right.

The Action Alarm and the 24V-12V power converter are installed behind the storage bin (7).The dash panel must be removed to access these components.

INSTRUCTOR NOTE: The instrument cluster and the new monitoring system will bediscussed in more detail, later in this presentation.


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Below the dash is the service brake pedal (1) and the decelerator pedal (2). The service brakepedal applies the service brakes (both left and right) proportionately with the amount of pressureapplied by the operator. When depressed, the pedal provides a signal to the Power Train ECMfrom the rotary position sensor connected to the pedal. The Power Train ECM then signals theelectronically controlled brake valve. When completely depressed, the brakes are fully engaged.

The smaller pedal on the right is the decelerator pedal. During normal operation, the machineoperates at high idle. Depressing the decelerator pedal decreases the engine rpm by a signal tothe Engine ECM from the rotary position sensor connected to the pedal.

Intermediate engine speeds are attained in the following manner. Set the high/low idle switch tothe HIGH IDLE position, and then depress the decelerator pedal to the desired engine speed.Then, press and hold the high idle (rabbit) side of the high/low idle switch for approximatelythree seconds. Then release the switch to set the intermediate engine speed. The engine speedmay then be reduced from this intermediate engine speed by depressing the decelerator pedal.When the decelerator pedal is released, the engine speed will return to the intermediate setting.The intermediate engine speed setting may be cancelled by pressing either the high idle (rabbit)or low idle (turtle) side of the switch again.


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The status of the brake pedal position sensor (percent of duty cycle/percent of pedal position)and the secondary brake switch may be viewed through the Advisor panel (Service/SystemStatus/Powertrain screens) or by using Cat ET.

The status of the decelerator pedal position sensor (percent of duty cycle/percent of pedalposition) may be viewed through the Advisor panel (Service/System Status/Engine screens) orby using Cat ET.


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The Power Train ECM (1) and the Implement ECM (2) are located at the rear of the cab. ThePower Train ECM can be accessed by removing the operator seat and the sound panel at the rearof the cab. The panel under the right console must also be removed to access the ImplementECM. Other components and service points located here are:

3. J1/P1 connector for the Implement ECM4. J2/P2 connector for the Implement ECM5. J1/P1 connector for the Power Train ECM6. J2/P2 connector for the Power Train ECM7. external lighting relays8. 24V DC to 12V DC power converter (attachment)

NOTE: The Implement ECM and Power Train ECM code plugs are tied to the wiringharness, which is routed through the channel below the ECMs. The 24V to 12V powerconverter shown above is used to power accessories other than the standard machineequipment. It is an attachment that can be ordered from the factory. If the powerconverter is not ordered from the factory, the connectors will be present in this locationand a converter can be added later. If the machine is equipped with Product Link, thatECM is located above the cab headliner.


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CATERPILLAR MONITORING AND DISPLAY SYSTEM, WITH ADVISOR™

The monitoring system for the D10T has been upgraded to the Caterpillar Monitoring andDisplay System with Advisor. This system is standard equipment for the T-Series Track-typeTractors.

The major components in the new monitoring system consist of the Advisor graphical displaymodule (1) and the in-dash instrument cluster (2). The graphical display module has a self-contained ECM (Advisor ECM).

Cat Advisor allows the operator to configure machine and implement operation and Advisordisplay options, and then save them to an operator profile that may be selected whenever theoperator desires.

Advisor also allows the serviceman to configure certain password protected machine functionsand to view system status information for the engine, the power train, the steering, and theimplement systems. The serviceman can also use the Advisor panel to perform calibrations ofthe machine and implement controls, the brakes and the transmission, and the steering system.


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The Caterpillar Monitoring and Display System (CMDS) continuously monitors all machinesystems. CMDS consists of both software and hardware components. The hardwarecomponents consist of the Cat Advisor graphical display module, a sealed instrument cluster, theEngine ECM, the Implement ECM, the Power Train ECM, the Action Alarm, the rear ActionLamp, and various switches, sensors, and senders. If the machine is so equipped, the CMDSmay also include connections to a Product Link ECM, a Computer Aided Earthmoving System (CAES).

The CMDS components communicate with each other and with electronic controls on themachine’s components through the Cat Data Link and through Controller Area Network (CAN)Data Links. A machine with standard equipment uses the Cat Data Link, the CAN A Data Link,and the CAN C Data Link. With AutoCarry attachments, CMDS will also include a CAN BData Link (shown in dashed lines, above) and a CAN D Data Link (not shown, above).

Advisor constantly monitors all of the ECMs, the alternator R-Terminal, the system inputvoltage, and the fuel level sensor. Advisor then drives the instrument cluster and activates itsmode and alert indicators, its displays, and its gauges. This information may also be accessedand displayed on Advisor’s screens or with Cat ET.


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In addition to the four analog gauges, the tachometer, and the LCD display screen (mentionedearlier), the instrument cluster contains up to fifteen LED indicators that show the operator thestatus of a number of machine functions. When lit, they indicate the following functions:

1. Engine pre-lube activated (active only if equipped with a pre-lube system)2. Winch Disabled (not functional for the D10T)3. Winch Low Speed Lock (not functional for the D10T)4. Winch Freespool or Release (not functional for the D10T)5. Auto KickDown Activated6. AutoShift Activated7. Parking Brake ON8. Action Lamp9. Charging System Fault (abnormal output at the "R" terminal)

10. Auto Blade Assist Enabled (active only if the machine is equipped with ABA)11. AutoCarry Active (active only if the machine is equipped with AutoCarry)12. Implement Lockout Activated13. FLOAT Active14. Single Tilt Enabled15. Dual Tilt Enabled (active only if the machine is equipped with dual tilt)


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The heart of the CMDS is the graphical display module, which is located on the right console,ahead of the dozer control lever. The graphical display module is referred to as Advisor.

Advisor consists of the display screen (1), the navigational buttons (2), and an internal, self-contained ECM (not visible).

Advisor is used to access, monitor, and display operating characteristics, diagnostics and events,and modes of operation. Advisor is also used to view and change operator preferences andparameters, much like the Vital Information Display System (VIDS) in previous D10R andD11R Track-type Tractors.

Advisor also allows the serviceman to troubleshoot and adjust machine systems by:

- viewing active and logged codes and events, and clearing logged codes;

- viewing the status of machine systems and their components; and

- performing calibrations for the steering, the implement, and the power train systems.


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Cat Advisor is the interface between the operator or serviceman and the CMDS. Information isdisplayed on a backlit LCD screen.

The top portion of the screen is called the "Top Banner" and it displays vital machineinformation at all times. The Top Banner may display different information from machine tomachine, depending on the attachments and the machine configuration. On the base machine,the banner displays:

- Transmission Gear and Direction, at the left;- Dozer Mode, in the center;- AutoShift Mode, at the right.

The Transmission Gear and Direction display area shows the transmission gear and directionthat is currently selected. The display may show any of the following transmission gear anddirection combinations: "1F, 2F, 3F, 1R, 2R, 3R, or 1N."


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The Dozer Mode display area can display a number of messages which show the current dozermode, the current segment during the Auto Blade Assist (ABA) cycle or AutoCarry cycle, or thestatus of the implement or the implement system. The Dozer Mode display area may show anyof the following messages:

- Carry (CARRY segment active - blade is in CARRY position)- Spread (blade is moving from CARRY to a preset SPREAD position)- Ready To Return (blade is at end of SPREAD segment - gear is Neutral)- Return (blade has reset - not in Forward gear)- Ready To Carry (blade is loading, next move will position for CARRY)- Manual (Manual blade mode active - ABA or AutoCarry not armed)- Not Reset (ECM does not know blade position)- Resetting (blade automatically moving to find load position)- Float (blade is in FLOAT - dozer control lever is in FLOAT position)- Low Engine Speed (engine speed too low for ABA/AutoCarry modes)- Wrong Gear (wrong gear for AutoCarry mode - shift the transmission to 1F)- Service (displayed during implement calibrations)- Implements Off (Implement Shutoff is ON, or active)- Stowing Ripper (ripper moving to stow position - AutoStow activated)

The AutoShift Mode display area shows the current AutoShift Mode that is selected, using theAutoShift Mode selector switch on the right operator console. Depending on how the tractor isconfigured, it can display "1F-2R," "2F-2R," "2F-1R," or "Inactive," if no AutoShift Mode isselected.

The bottom portion of the Advisor display screen is the Data Display/Menu Selection DisplayArea. It displays numerous menus and sub-menus used for navigation from screen to screen. Itmay also display operator warnings, system information, and system status, depending on whatmenu or sub-menu selection has been made.

A "More Options" icon may also appear on the display screen. This is an indicator that moreinformation is available for selecting or displaying from the current highlighted position. Thisicon may point down, up, left, or right. Using the Arrow Button that corresponds to the "MoreOptions" icon will allow the operator or serviceman to move to and/or view the additionalinformation.

At the right of the display screen is a column of five User Interface buttons. These buttons areused to navigate through the numerous Advisor screens, to make menu selections, or to enterdata.


The five User Interface buttons, from top to bottom, are:

1. LEFT/UP Arrow button - This button is used for screen navigation or data entry. It can beused:- to scroll up a vertical list or scroll left across a horizontal list;- to decrease a setting value, such as decreasing brightness/contrast.

2. DOWN/RIGHT Arrow button - This button is also used for screen navigation or data entry.It can be used:- to scroll down a vertical list or scroll right across a horizontal list;- to increase a setting value, such as increasing brightness/contrast.

3. BACK button - This button is used:- to go up one level in a stair-step (hierarchical) menu structure, or to return to the

previous screen, much the same as the BACK button is used in Windows InternetExplorer™;

- as a backspace or cancel key when the operator or serviceman wishes to delete enteredcharacters.

4. HOME button - This button is used to return to the home menu screen, regardless of whatscreen is currently displayed.

5. OK button - This button is used:- to make selections from a screen;- to confirm an entry, such as a password, or for saving an operator profile entry.

Navigation through the menus and sub-menus is accomplished by using the ARROW buttons tohighlight the desired selection, then pressing the OK button. The ARROW buttons are also usedto highlight a mode or to set a parameter. Pressing the OK button selects that option. (Example:Choosing either "Enabled" or "Disabled" for the FLOAT option in the Implement Settingsmenu.)

NOTE: The column of five buttons at the left of the display screen currently have nofunction.



OK

1F 1F-2R

FloatRecall Operator Settings

OKOK

Default SettingsActivated in 10 Seconds

OrPress

To RecallPrevious Settings

Start-up

Advisor will perform a self-test routine at machine start-up (key ON). After a few seconds, apreliminary screen will appear (illustration No. 19). The preliminary screen displays, "DefaultSettings Activated in 10 Seconds Or Press OK To Recall Previous Settings." To use the operatorprofile (settings) that were active the last time the machine was operated the operator mayacknowledge "YES" by pressing the OK button. NO is assumed by waiting 10 seconds.

If the operator answers YES by pressing the OK button, Advisor will load into its memory theoperator profile that was last used.

If the operator waits 10 seconds, the default settings (or factory settings) will be loaded intoAdvisor's memory.

In either situation, if the operator wishes to use an operator profile (settings) other than theprofile last used or the default settings, another operator profile may be selected from the"Operator" menu selection, from the Home Menu.

After the preliminary screen has been acknowledged or has expired, "pop-up" warning screensmay be displayed if there are any active faults in any of the machine systems (see illustrationNo. 20).

19


OK

1F 1F-2R

Float

Engine ECMMID 36 ID 164-3

Injection Actuation Pressure Sensor

Voltage Above Normal Shorted High

ACKNOWLEDGEPRESS THE OK KEY TO ACKNOWLEDGE

!

The illustration above shows a "pop-up" warning screen generated by the Engine ECM andreported by Advisor. There may be more warning screens if there are any other active faults orevents reported to Advisor by the Engine ECM, or any other ECM on the machine. Advisor willscroll through all of the warning screens generated by all of the active faults and events. Each ofthese warning screens must be individually acknowledged by pressing the "OK" button.

Each of these warning screens contains the following information:

- The reporting ECM (in text)- The reporting MID (module identifier, or ECM code)- The ID (Component ID and Failure Mode Identifier)- A text message stating the failed component- A text message stating the failure mode of the component- A prompt for the operator to acknowledge the warning

Acknowledging these warnings does not clear them from the reporting ECM's memory.Acknowledging them only clears them from the screen, or "snoozes" them. They may re-occurafter a pre-determined amount of time, depending on their severity.

The CMDS provides three Warning Category Indicators (levels), utilizing "pop-up" warningmessages on Advisor's screen (see above), the front Action Light (contained in the instrumentcluster), the rear Action Lamp, and an Action Alarm.

20

The three warning category indicators and the resulting combinations of the Action Lamps andthe Action Alarm are:

- Warning Category Indicator 1: A warning appears on the Advisor screen, describingthe event or diagnostic failure. The forward Action Lamp will illuminate to solid amber.The warning can be acknowledged (snoozed) by pressing the OK button, and will not re-appear for several hours, depending on the failure or event (or if the event or failure doesnot re-occur).

- Warning Category Indicator 2: A warning appears on the Advisor screen, describingthe event or diagnostic failure. The Action Light and Lamp will flash red, alerting theoperator to change the machine operation mode. The warning can be acknowledged(snoozed) by pressing the OK button, and will not re-appear for one hour, depending onthe event or failure (or if the event or failure does not re-occur) and the Action Light andLamp will stop flashing.

- Warning Category Indicator 3: A warning appears on the Advisor screen, describingthe event or diagnostic failure. The Action Light and Lamp will flash red, and the ActionAlarm will pulse to alert the operator to shut down the machine. The warning can beacknowledged (snoozed) and will continue to appear every five minutes. The ActionLight and Lamp will continue to flash red and the Action Alarm will continue to pulseafter the operator acknowledges the warning.

NOTE: If the Warning Category Indicator (fault) is related to an implement controlfailure, the Advisor warning will ask if the operator desires to go to "Limp Home Mode."If the operator chooses the YES option, Advisor will display the Limp Home Screen. TheLimp Home screen allows the operator to use Advisor to slowly and incrementally movethe implements to a position that will allow the machine to be moved for service work.Gear selection for the transmission will be limited to first gear forward, or first gearreverse in Limp Home Mode.

NOTE: At machine start-up (key ON), the LCD display in the Instrument Cluster willbriefly display the Instrument Cluster's part number. Although the T-Series tractors allhave a common cab, the Instrument Cluster is different for the D8T, the D9T, and theD10T. This is due mainly because of differences in engine rpm between these models.


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After the warning screens have been acknowledged the "Performance 1 of 2" screen will thenappear on the display (illustration No. 21). This is the default screen. Pressing the rightARROW button will display the "Performance 2 of 2" screen (illustration No. 22).

Using the left and right ARROW buttons allows the operator to switch back and forth betweenthe two Performance screens. Vital information about the machine's major systems may beeasily monitored using these two screens and the in-dash Instrument Cluster.

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22


The two Performance screens display real-time text information for the following:- Engine Coolant Temperature- Engine Speed- Hydraulic Oil Temperature- Torque Converter Oil Temperature- Engine Oil Pressure- Air Inlet Temperature (engine intake air temperature)- Fuel Level- System Voltage

The Home Menu may be displayed from any screen by pressing the HOME button.

NOTE: If the screen contrast, the screen backlight, or the display language is set suchthat the operator or serviceman cannot see or read the display, a simple reset mode hasbeen added to the most recent software for Advisor. The following procedure will helpovercome this problem:

1. Set the key switch to OFF and then back to ON.2. Wait approximately 15 seconds.3. If the Action Lamp is illuminated or flashing, press the OK button a number of times

until the Action Lamp is no longer illuminated. If the Action Lamp is not illuminated,proceed to step 4.

4. Press and hold the OK button for five seconds.

Performing this procedure will cause the brightness and contrast to be reset to 50% andthe screen will display the language selection menu. The operator or serviceman maythen select the desired language.

The above information supercedes the Service Training publication SERV1790,"Caterpillar Monitoring and Display System with Advisor™ for Track-type Tractors."

INSTRUCTOR NOTE: For more detailed information about the new monitoringsystem and Advisor and how to access and use all of the options, refer to SERV1790(STMG 790), "Caterpillar Monitoring and Display System with Advisor™ for Track-typeTractors."

SERV1790 also contains several structured, hands-on lab exercises that require thestudents to create operator profiles, change machine settings and save them, access andrecord machine systems status information, and perform several machine systemcalibrations.

When used in conjunction with this presentation, STMG 790 will provide a thoroughunderstanding and a practical application of this informational and diagnostic tool.


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ENGINE

The C27 ACERT™ technology engine is new for the D10T Track-type Tractor. The engine isequipped with Mechanical Electronic Unit Injection (MEUI), an electro-hydraulic demand fansystem, and a Remote Air To Air AfterCooler (RATAAC).

The C27 engine also utilizes the A4 Engine Electronic Control Module (ECM), which is aircooled. The C27 is rated at 432 kW (580 horsepower) at 1800 rpm.

The C27 engine is a 12 cylinder "V" arrangement with a displacement of 27 liters. Most of theservice points for the C27 have been located on the left side of the engine.

The C27 ACERT engine meets U.S. Environmental Protection Agency (EPA) Tier III EmissionsRegulations for North America and Stage III European Emissions Regulations.

Engine oil and filter change intervals have been increased to 500 hours, under most operatingconditions. However, engine load factor, sulfur levels in the fuel, oil quality, and altitude maynegatively affect the extended oil change intervals. Regular engine oil samplings (S•O•S) mustbe performed every 250 hours to confirm oil cleanliness.


The C27 is mechanically similar to the 3412E engine used in the D10R, except that a camshaftis now located in each cylinder head, instead of a single camshaft in the engine block. The geartrains for the camshafts have been moved to the rear of the engine. The Engine ECM and itssoftware, the cams, the injectors, the crankshaft, the piston rods, the pistons, and a few othercomponents are also different, reflecting the ACERT technology.

An elctro-hydraulic demand fan is standard equipment for the D10T and may be equipped withan automatic/manual fan reversing feature for those applications requiring it.

The engine performance specifications for the D10T Track-type Tractor are:

-.Serial No. Prefix: EHX- Performance Spec: 0K4650 (for North America)- Max Altitude: 3657 m (12,000 ft.)- Gross Power: 483 kW (648 hp)- Net Power: 433 kW (580 hp)- Full Load rpm: 1800- High Idle rpm (full throttle, neutral): 2010 ± 10 (for North America), 1970 ± 10 (for E.U.)- Low Idle rpm: 700

NOTE: The C27 engine uses a "Ground Speed Governor" software strategy to preventengine overspeed and to maintain a constant speed in downhill and uphill situationswhen there is little or no load on the blade. The Engine ECM constantly monitorsengine speed and torque converter output speed to make the following adjustments.

- If the engine is at high idle while the machine is traveling downhill, the Engine ECM willautomatically lower engine rpm to maintain the correct torque converter output speed. Inuphill situations, the Engine ECM will automatically increase engine rpm to maintain thecorrect torque converter output speed, up to a maximum of 2000 rpm.

- If the operator has set an intermediate engine speed using the decelerator and the high-low idle switch, this strategy is ignored in uphill situations.

NOTE: On machines built for the E.U., the torque converter output speed target isapproximately 5% lower than those built for North America, due to more stringent noiserequirements. Accordingly, the ground speed target is a bit slower, also. This will resultin slightly slower speeds when "roading" the machine and when backing up.


24

Major components and service points accessible from the left side of the engine are:

1. air conditioning compressor

2. secondary fuel filter

3. two engine oil filters and associated service points (discussed later in this presentation)

4. engine oil fill tube

5. engine oil dipstick

6. left side air filter

7. left side gear train lube line (engine oil)

8. starter

9. left side turbocharger


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34 5 6

8

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9

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Major components and service points accessible from the right side of the engine are:

1. Engine ECM

2. coolant sampling port (S•O•S)

3. alternator

4. external engine oil cooler

5. twin powertrain oil coolers (the engine oil cooler is behind the powertrain oil coolers)

6. right side turbocharger

7. right side gear train lube line (engine oil)

8. right side air filter

NOTE: The exhaust manifolds, the turbine side of the turbochargers, and the exhaustpipes connecting the turbochargers to the mufflers are covered with "soft wrap" insulation,or heat shields. This insulation is used to prevent pre-heating the outside air that is drawnin through the engine compartment doors by the hydraulic demand fan. This air is usedfor cooling purposes (the radiator, the hydraulic oil cooler, and the standard airconditioning condenser).


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26

The 10-micron primary fuel filter (1) and water separator (7) are located in the compartment atthe rear of the left fender. The primary fuel filter is mounted to the front of the fuel tank. Theprimary fuel filter contains a water separator (2) which removes water from the fuel. Water in ahigh pressure fuel system can cause premature failure of the fuel injectors due to corrosion andlack of lubricity. Water should be drained from the water separator daily, using the drain valvelocated at the bottom of the filter.

Fuel is drawn from the primary fuel filter by the fuel pump (shown later) and is then directed tothe secondary fuel filter (not shown, above). The secondary fuel filter removes contaminantsthat could damage the fuel injectors. The fuel filters should be replaced regularly, according tothe guidelines in the D10T Operation and Maintenance Manual (SEBU7764), to ensure thatclean fuel is always delivered to the fuel injectors.

The electric fuel priming pump (3) is integrated into the primary fuel filter base. It is activatedby activating the electric fuel priming pump switch (4). The fuel priming pump is used to fillthe fuel filters after they have been replaced. The fuel priming pump is capable of forcing theair from the entire fuel system.


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7

After the fuel filters have been replaced, activate the priming pump and then crack open the fuelline fitting at the outlet of the primary fuel filter to purge all air from the primary fuel filter, thefuel line, and the priming pump. (Always place a suitable container under the primary fuel filterto collect any fuel that escapes through the fitting while purging air from the system.)

Trapped air and intermittent fuel will escape through the fuel line fitting as the pump primesitself. When the fitting emits only fuel, the fitting should then be re-tightened. At the sametime, continue operating the priming pump until it is determined that all air has been forced fromthe entire fuel system - from the priming pump back to the fuel tank.

The priming pump produces enough pressure to force fuel past the bypass valve in the fueltransfer pump and past the fuel pressure regulator.

Note that the main disconnect switch must be turned to the ON position and the key start switchmust be in the OFF position for the fuel priming pump to operate.

Also shown in illustration No. 26 is the fuel shutoff valve (2). When the shutoff valve handle ismoved to a position that is perpendicular to the fuel line, the flow of fuel from the fuel tank tothe primary fuel filter is shut OFF.

The fuel supply line (6) connects the fuel tank to the fuel priming pump and the primary fuelfilter.

The fuel return line (5) directs unused fuel from the fuel pressure regulator back to the fuel tank.


27

The fuel transfer pump (1) is located on top of the engine, at the rear. The fuel transfer pump isinstalled in the front side of the timing gear cover and it is driven by a gear in the rear gear train.The fuel transfer pump draws fuel from the primary fuel filter through a fuel line connected tothe pump inlet port (3). The fuel pump forces the fuel through the pump outlet (2) to thesecondary fuel filter, which is located at the left, front of the engine.

Also shown in illustration No. 27 is the fuel pressure regulator manifold (4). Unused fuel fromthe fuel gallery in the left cylinder head enters the manifold at the top inlet (6). Unused fuelfrom the fuel gallery in the right cylinder head enters the manifold at the rear inlet (5). The fuelpressure regulator is a check valve (8) that is installed in the front of the manifold. The fuelpressure regulator maintains the fuel pressure at approximately 550 kPa (80 psi), with a full loadon the engine (torque converter stall).

Fuel that flows past the fuel pressure regulator is directed back to the fuel tank through a fuelline connected to the manifold outlet port (7).


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The 4-micron secondary fuel filter (1) is located in front of the engine oil filters, at the left frontof the engine. The fuel temperature sensor (5), the fuel pressure sensor (4), the fuel pressure testport (3), and the fuel pressure differential switch (2) are installed in the secondary fuel filter base.The fuel filter pressure differential switch (5) compares the filter inlet pressure to the filter outletpressure. This switch is normally closed. If the secondary fuel filter becomes clogged, thedifference between the filter inlet pressure and the filter outlet pressure causes the switch to openand the Advisor panel will warn the operator, "Fuel Filter Is Plugged - Change Fuel Filter Soon."

When this event occurs, engine performance may be degraded when the fuel flow is restricted,and the fuel injectors are starved of fuel. This condition, if ignored, could cause damage to thefuel injectors.

The fuel pressure test port (3) will allow the serviceman to test the fuel pressure. The test port issituated at the outlet of the secondary fuel filter.

The status of the fuel pressure sensor, the fuel temperature sensor, and the filter pressuredifferential switch may be viewed through the Advisor panel (Service/System Status/Enginescreens) or by using Cat ET.


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The two engine oil filters (1) are located at the left front of the engine, behind the secondary fuelfilter. The engine oil sampling (S•O•S) port (5) is located on the front of the outer filter base.The S•O•S port provides an oil sample before the oil is filtered.

The engine oil pressure test port (2) is located behind the filters and is positioned at the oil filteroutlet (after oil filtering).

Also shown in illustration No. 29 is the engine oil dipstick (3) and the engine oil fill tube (4).


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A number of engine sensors are located on top of the engine, near the front. These sensors are:

1. left intake manifold air pressure (boost) sensor2. engine coolant temperature sensor3. atmospheric pressure sensor4. right intake manifold air pressure (boost) sensor5. intake air temperature sensor

Boost pressure (both left and right) may be read on the status screen in Cat ET. The boostpressure is a calculation of the difference between the signal from the atmospheric pressuresensor and the signal from the intake manifold air pressure sensor. On the C27, the signals fromboth the left and the right intake manifold air pressure sensors are used by the Engine ECM tocalculate boost for the left and the right cylinder banks. A failure of an intake manifold airpressure sensor can cause the Engine ECM to perceive a "zero boost" condition, resulting in areduction in power by as much as 60%.

The status of all five of these engine sensors may be viewed through the Advisor panel(Service/System Status/Engine screens) or by using Cat ET. The intake manifold airtemperature may also be viewed on the Advisor panel in the Performance 2 screen.


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NOTE: The Engine ECM only uses the right intake manifold air pressure sensor for calculatingthe air-to-fuel ratio. If the right intake manifold air pressure sensor fails, engine derate willoccur. The engine derate is mainly caused by the Engine ECM's inability to calculate the air-to-fuel ratio and/or boost pressure.

The left intake air pressure sensor is only used to calculate "boost" pressure for the left cylinderbank. Cat ET may be used to compare the left and right intake air pressures for diagnostic andtroubleshooting purposes, such as turbocharger failure or air filter restriction.

NOTE: The signal from the atmospheric pressure sensor is used by the Engine ECM tocalculate a number of pressure measurements in most electronic engines. The signal from theatmospheric pressure sensor is compared to the signal from the other engine pressure sensors todetermine the following:

- ambient (absolute) pressure is the atmospheric pressure;

- boost pressure is determined by comparing the atmospheric pressure (sensor) to the intakemanifold air pressure (sensor);

- engine oil (gauge) pressure is determined by comparing the atmospheric pressure (sensor)to the engine oil pressure (sensor);

- air filter restriction is determined by comparing the atmospheric pressure (sensor) to theturbo inlet pressure (sensor);

- fuel (gauge) pressure is determined by comparing the atmospheric pressure (sensor) to thefuel pressure (sensor).

Also, when the engine is started, the Engine ECM uses the signal from the atmospheric pressuresensor as a reference point for calibration of the other pressure sensors on the engine (if the keystart switch is turned to ON for at least five seconds before the engine starts).


The primary speed/timing (crankshaft speed) sensor (1) is located at the lower, left front of theengine, behind the crankshaft damper. This sensor provides engine speed information to theEngine ECM. This information is also shared with the Power Train ECM through the CAT datalink, eliminating the need for an engine output speed sensor.The starter (2) is installed on the front side of the flywheel housing, at the left rear of the engine.A second starter can be installed in the same place on the right side of the engine if the tractor isequipped with a cold weather arrangement. The ports for inserting the 9S9082 engine turningtool and the TDC timing pin (not visible) are also located on the front side of the flywheelhousing, above the starter mounting port.An engine block heater element (3) is an attachment installed on tractors with a cold weatherarrangement. A second block heater element would be installed on the right side of the engine,in the same location if the machine is equipped with the cold weather arrangement.

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The ecology drain for engine oil (1) is located on the front of the engine oil pan. It may beaccessed through a plate in the bottom guard, directly below the drain valve.

The engine pre-lube pump (3) is mounted to the inside of the left frame rail, adjacent to theengine oil pan (4), if the machine is equipped with this attachment. The engine pre-lube pump (3) is driven by an electric motor (2). (The pre-lube pump is no longer driven by thestarter motor, as in previous models.)

The engine pre-lube strategy prevents premature wear of critical engine components by ensuringa minimum engine oil pressure throughout the engine oil system before the engine starts.

When the key start switch is moved to the START position, the engine prelube pump may runfor a short time before the starter engages.

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3

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4

The Engine ECM determines when to activate the engine pre-lube pump by monitoring theengine oil pressure sensor. If the oil pressure is less than 30 kPa (4.4 psi) the Engine ECM willactivate the pre-lube pump until the oil pressure reaches 30 kPa (4.4 psi), or for a maximum of45 seconds, whichever occurs first.

To override the engine pre-lube strategy, turn the key start switch to the START position. Thencycle the key start switch to the OFF position and then back to the START position again withinone second. This action will allow the starter to engage without cycling the engine pre-lubepump.

NOTE: When the pre-lube cycle is activated, Advisor will inform the operator thatengine pre-lube is activated. Additionally, Advisor will instruct the operator to keep thekey start switch in the "START" position until the engine cranks and runs.


The starter disconnect switch (1) and the main electrical disconnect switch (2) may be accessedby opening a spring-hinged door, located between the left engine compartment door and thefront step on the left fender. The starter disconnect switch will disable the starter(s) when theswitch is set to the OFF position. The auxiliary start connector (4) is installed in this samecompartment. A block heater receptacle (3) is also located here if the machine is equipped withthe cold weather arrangement. (A 120V AC or a 240V AC version of the block heater isavailable.)

The ether aid solenoid (5) and the ether bottle mounting bracket (6) are located beneath theelectrical disconnect switches (the ether canister is not installed). When the ether aid solenoid isenergized, ether is injected into the intake manifold inlet tube through the small diameter line (7)to aid in starting the engine in cold weather.

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The Engine ECM controls ether injection when the conditions warrant its use. The Engine ECMmonitors the intake air temperature sensor and the coolant temperature sensor to determine whenether injection is required. If the temperature of the engine coolant or the intake air is less than0°C (32°F), AND the engine speed is greater than 35 rpm, but less than 700 rpm (low idlespeed), then ether injection will be activated. Once the engine starts and the low idle speed isattained, the Engine ECM then looks to the ether injection map (contained in the enginesoftware) to determine how long and how often to provide ether injection. This helps attainemissions regulations by eliminating white smoke when the engine is first started.

The status of the ether aid solenoid may be viewed through the Advisor Panel (Service/SystemStatus/Engine screens) or by using Cat ET.


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The coolant temperature regulator (thermostat) housing (1) is located at the right front of theengine. Two thermostats are contained in the thermostat housing. When the jacket water is coldand the thermostats have not yet opened, jacket water is diverted directly back to the jacketwater pump through the bypass tube (3). The jacket water pump forces coolant through theengine oil cooler and the power train oil coolers before the coolant enters the engine block andthen the cylinder heads.

Jacket water (coolant) samples (S•O•S) may be taken at the coolant sampling port (2), which isidentified by the green protective cap. Coolant samples should be taken only when the engine isat operating temperature and the coolant is circulating through the entire system.

Always use a clean, lint-free towel to clean the test port prior to taking a fluid sample. Alwaysreplace the protective cap after a fluid sample has been taken. Doing so will prevent damage tothe test port and lessen the likelihood of introducing contamination into subsequent fluidsamples.

The jacket water pump (4) is also located at the right front of the engine, below the thermostathousing.


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The air cooled A4 Engine ECM (1) is installed above the right front valve cover. The J1/P1connector (2) is a 70-pin connector and the J2/P2 connector (3) is a 120-pin connector.

There is no timing calibration probe connector on the C27 engine. The timing calibration probeis permanently installed in the engine flywheel housing (shown later). The probe is alsopermanently wired into an engine wiring harness, so that no cable is needed to connect the probewith the Engine ECM.

NOTE: The Engine ECM is not cooled using fuel. The Engine ECM is air cooled.


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The engine oil pressure sensor (1) is installed in the top front of the right cylinder head, betweenthe front valve cover and the front timing gear cover.

The secondary (camshaft) speed/timing sensor (2) is installed in the rear of the timing gearcover, at the right front of the engine. This sensor reads the pick-up teeth on the rear face of thecam balance gear. The balance gear is attached to the front of the right camshaft.

The fuel supply line for the right cylinder head (3) is also visible above.

The status of the engine oil pressure sensor may be viewed through the Advisor Panel(Service/System Status/Engine screen and the Performance 2 screen) or by using Cat ET.


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The turbo inlet pressure sensor (1) is installed in the rear of the manifold that connects the leftand right air filter canisters. The Engine ECM compares the signal from the turbo inlet airpressure sensor to the signal from the atmospheric air pressure sensor and calculates thedifference between the two pressures. If the pressure differential is too great, it can indicate thatthe air filter is clogged and needs to be replaced. Too great a pressure differential (airrestriction) will cause the engine to derate and will degrade engine performance.

The "Crank-Without-Inject" connector and plugs (2) are fastened to the wiring harness belowthe right air filter canister.

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Removing the plug (4) from the "Crank-Without-Inject" connector (3) and inserting the plug atthe right (5) will electronically disable the fuel injectors. This allows the engine to be turned(cranked) using the starter, but without the engine starting. No fuel will be injected into thecylinders in this mode. The engine cannot start and run.

The status of the turbo inlet pressure sensor and the "Crank-Without-Inject" status may beviewed through the Advisor panel (Service/System Status/Engine screens) or through Cat ET.

NOTE: When using the "Crank-Without-Inject" feature, always ensure that the eitheraid solenoid is unplugged before using the starter to turn the engine. Even though thefuel injectors are electronically disabled, the Engine ECM will command ether injectionif all of the requirements (conditions) that require ether injection are met. The enginewill try to start and run with ether injection.4


The external engine oil cooler is an oil-to-water type cooler. Engine oil flows from the engineoil pump into the rear of the engine oil cooler (1) where it flows around tubes filled withcoolant. When the oil is cold, some of the oil flows through the cooler bypass tube (not visible).Engine oil flows to the front of the cooler where it exits the front of the oil cooler and then flowsto the oil filters (shown earlier). From the oil filters, the engine oil enters the oil gallery in theengine block where it is used for lubrication purposes. Coolant from the jacket water pumpflows into the front of the cooler through the coolant inlet (5). The engine oil cooler is inparallel with the two power train oil coolers (2).

The hot coolant supply line to the cab heater connects to the lower water shutoff valve (3). Thereturn coolant line from the cab heater connects to the upper water shutoff valve (4).

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6

The coolant flow switch (6) is installed in the inlet bonnet of the external engine oil cooler.

The timing calibration probe (7) is installed at the factory. The probe is located above themounting position of the right side starter, on the front of the flywheel housing (forward of theright rear engine mounting pad). The probe is permanently wired into the Engine ECM. Nocables are needed to make the connection between the probe and a connector when performingan engine timing calibration routine.

The status of the coolant flow switch may be viewed through the Advisor panel (Service/SystemStatus/Engine screens) or through Cat ET.

NOTE: When troubleshooting the cooling system, it must be understood that both theengine oil cooler and the power train oil coolers are heat sources that raise thetemperature of the coolant before it enters the engine block.


The C27 ACERT engine contains a cam in each cylinder head, instead of a single cam in theengine block, as in the 3412E engine that was used in the D10R. The timing gear train for theC27 has been moved to the rear of the engine. Illustration No. 44 shows the front gear train withthe front gear cover removed. The components identified in illustration No. 44 are:

1. idler gear (drives the oil pump drive gear)2. front crankshaft gear3. idler gear4. idler gear for the jacket water pump drive gear (not shown)

Note that the timing marks on the gears of the front gear train are not used for any purpose.

44

45


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9 10 11

12

Illustration No. 45 shows the rear timing gear train of the C27 with the rear gear train coverremoved. The components identified in illustration No.45 are:

5. rear crankshaft gear6. idler gear (drives the implement pump and powertrain oil pump)7. idler gear (driven by gear No. 6)8. left camshaft drive/timing gear9. left camshaft timing mark (stamped into the machined surface)

10. idler gear (drives both camshafts and the fuel transfer pump)11. right camshaft timing mark (stamped into the machined surface)12. right camshaft drive/timing gear

When the TDC timing pin is used to locate the Top Dead Center position, cylinder No. 1 will beat TDC of the compression stroke and cylinder No. 11 will be at TDC of the exhaust strokewhen the timing marks on the camshaft gears are aligned with the timing marks on the rear gearhousing (see illustration No. 45).

The firing order for the C27 engine is: 1, 10, 9, 6, 5, 12, 11, 4, 3, 8, 7, 2.

The rear timing gear cover has an inspection cover behind either camshaft gear that will allowthe serviceman to examine the timing marks, in order to determine the exact relational positionsbetween the camshaft and the crankshaft.

INSTRUCTOR NOTE: Servicemen must be informed that the procedure for findingTDC on the compression stroke (cylinder No. 1) is different for C27 ACERT engines usedin the first D10T tractors built, as compared to the TDC procedure described earlier.This information is extremely important when checking or setting valve lash or whensetting fuel injector height. The procedure for these early production engines is:

- When the TDC timing pin is used to locate the Top Dead Center position, cylinder No. 1will be at TDC of the exhaust stroke and cylinder No. 11 will be at TDC of thecompression stroke when the timing marks on the camshaft gear are aligned with thetiming marks on the rear gear housing (see illustration No. 45).

- When the crankshaft is rotated another 360° and is pinned again at the Top Dead Centerposition, cylinder No. 1 will be at TDC of the compression stroke and cylinder No. 11 willbe at TDC of the exhaust stroke when the timing marks on the camshaft gear are 180° offthe timing marks on the rear gear housing.

The TDC strategy will change some time in the future to reflect the standard timingstrategy used for the 3412E, but engines used early in the production schedule of theD10T will reflect the information described above. Always refer to the latest revision ofthe C27 Engine Specifications manual (Form No. SENR9936) for more detailedinformation about these procedures and for the serial number break that indicates whichstrategy is used for the engine in the machine in question.


The two turbochargers used on the C27 do not use a wastegate.

The turbocharger bearings are lubricated with engine oil. Oil supply is through the upper oilline (1). Oil returns to the engine block through the lower oil line (4). Engine coolant is used tocool the turbocharger bearings. Coolant supply to the bearings is through the lower tube (3).Coolant return to the shunt tank is through the upper tube (2).

Illustration No. 47 shows the fuel heater (5) that is an attachment included in the cold weatherarrangement. The fuel heater is mounted to the inside of the left fender, forward of the leftrollover support post and under the floor of operator's compartment.

46

47


1

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3 4

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9

Fuel is heated using the hot coolant supply from the cab heater lines. Hot coolant enters the fuelheater at the coolant inlet (7) and returns through the coolant outlet (8).

Fuel from the primary fuel filter is drawn through the heater by the fuel transfer pump. Fuelenters the fuel heater through the fuel inlet (6) and exits the heater at the fuel outlet (9), where itcontinues to the fuel transfer pump.

Fuel should not be heated in warmer weather. The water shutoff valves to the cab heater mustbe closed to disable the heating function of the fuel heater. The water shutoff valves are locatedon the right side of the engine and were shown earlier in this presentation (illustration No. 42).



The sonar type fuel level sensor (1) is installed on the underside of the fuel tank, near the center.The fuel tank is located at the rear of the machine.

The fuel level sensor is directly monitored by the Advisor ECM. The Advisor ECM thenprovides a signal to the analog type fuel level gauge in the instrument cluster. The Performance 2screen on the Advisor panel also displays a digital readout showing the percent of remaining fuel.

Advisor will alert the operator with a pop-up warning when the fuel level reaches 10% of tankcapacity (Warning Category Indicator 1). A second, and more severe pop-up warning will begenerated by Advisor (Warning Category Indicator 2) if the fuel tank reaches 5% of capacity.The fuel tank should be filled immediately if the second (Level II) warning is generated.

The fuel injectors can be badly damaged if they are starved of fuel, due to the lack of cooling andlubrication properties provided by the fuel.

The fuel tank will hold 1204 liters (318 U.S. gal.) of fuel.

48

1

49

Fuel Delivery System

Fuel is drawn from the fuel tank through the primary fuel filter (10-micron) and water separatorby a gear-type fuel transfer pump. The fuel transfer pump forces the fuel through the secondaryfuel filter (4-micron).

The fuel is then directed through a fuel line to a "tee" fitting that divides the fuel flow anddirects the fuel to both the left and right cylinder heads. The fuel enters the front of the cylinderheads and flows into the fuel galleries, where it is made available to each of the twelve MEUIfuel injectors. Any excess fuel not injected into the cylinders by the fuel injectors leaves therear of the cylinder heads and is directed to the fuel pressure regulator. The fuel pressureregulator maintains a fuel system pressure of approximately 560 kPa (80 psi).

The excess fuel flow returns to the fuel tank from the fuel pressure regulator. The ratio of fuelused for combustion and fuel returned to tank is approximately 3:1 (i.e. four times the volumerequired for combustion is supplied to the system for combustion and injector cooling purposes).


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A pressure differential switch is installed in the secondary fuel filter base and will alert theoperator, via Advisor, of a fuel filter restriction. The pressure differential switch compares thefilter inlet pressure to the filter outlet pressure. When the difference in the inlet and outletpressures causes the switch to activate, the Advisor panel will warn the operator that thesecondary fuel filter is clogged and that fuel flow is restricted. The secondary fuel filter will notbe bypassed. However, engine performance can be degraded due to the restriction of fuel flowto the injectors. If the restriction is too great, the injectors could be damaged because of thereduction in fuel flow that is used for cooling the injectors. The fuel used by the injectors alsoprovides lubrication qualities that protect the small component parts of the injectors.

The status of the fuel pressure differential switch may be viewed through the Advisor panel(Service/System Status/Engine screens) or by using Cat ET.


50

Engine Air System

Engine intake air is drawn into the engine air (rear) pre-cleaner (2) by the vacuum created by thecompressor wheels in the turbochargers (12).

The engine intake air is then drawn through the air filter inlet bonnet (6), which divides the airflow evenly to the left and right air cleaner canisters (8). Fine contaminants are removed by theair filter elements inside the canisters. The filtered engine intake air is then drawn into the airinlets of the turbochargers (11).

At the same time, exhaust gasses passing through both mufflers (4) flow past a dust ejector tube (3) in each exhaust stack. As the exhaust gasses flow past the ejector tubes (3), they createa (venturi effect) vacuum in the ejector tubes. The dust ejector tubes are connected to the pre-cleaner by flexible hoses (5). These connections create a secondary vacuum in the pre-cleanerhousing which serves to draw large contaminant particles from the engine intake air as it passesthrough the pre-cleaner. The large contaminant particles drawn through the ejector tubes and areejected through the exhaust stack.

The turbochargers compress the engine intake air and force it out of the compressor outlets andthen into the (red) RATAAC inlet tubes (10). The compressed engine intake air then enters boththe left and the right Remote Air To Air AfterCooler (RATAAC) heat exchanger cores (7).


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10 10

11 1112 12

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As the engine intake air passes through the RATAAC heat exchanger cores, the air is cooled andbecomes more dense. The engine intake air then exits the RATAAC cores through the RATAACoutlets. (Note that the engine intake air flow through the left RATAAC core is from front to rear.The flow of engine intake air through the right RATAAC core is from rear to front.)

The compressed, cooled engine intake air is then directed to the intake manifold through the(blue) intake air tubes (9). From the intake manifold, the engine intake air enters the cylinderheads. The cooler, more dense intake air then enters the cylinders through the intake valves in thecylinder heads. As the pistons rise in their respective cylinders, they compress the air. Thecompressed air then becomes super-heated. Combustion occurs when fuel is injected into thesuper-heated air at the top of the compression stroke of each piston. The combustion of thefuel/air mixture forces the pistons down. As the pistons are forced down, the energy is transferredto the crankshaft through the piston rods. As the crankshaft rotates, it causes the pistons to riseand fall in their respective cylinders.

As the pistons rise during their exhaust strokes, the exhaust gasses flow out of the exhaust valvesin the cylinder heads, where they enter the exhaust manifolds (behind the turbochargers).

The exhaust manifolds then direct the hot exhaust gasses into the inlets of the turbine side of theturbochargers. These hot, high-pressure gasses are used to power the turbine wheels as theyexpand and pass through the turbochargers. The turbine wheel is connected to the compressorwheel by a shaft in each turbocharger. As the turbines rotate, so do the compressor wheels.

The exhaust gasses then exit the turbochargers through the exhaust outlets (13), which direct thegasses to the mufflers (4) and the exhaust stacks.

Simultaneously, a hydraulically driven fan inside the RATAAC assembly draws cooling air intothe RATAAC through the forward pre-cleaner (1). The exhaust gasses passing through the leftmuffler (4) flow past the dust ejector tube (3) in the left exhaust stack. As the exhaust gasses flowpast the ejector tube (3), they create a (venturi effect) vacuum in the ejector tube. The dust ejectortube is connected to the pre-cleaner by a flexible hose (5). This connection creates the secondaryvacuum in the pre-cleaner housing which serves to draw large contaminant particles from the pre-cleaner through the tube. The large particles are then ejected through the left exhaust stack.

The cooling air is then forced through the assembly housing, flowing around left and right heatexchanger cores. As the cooling air passes through the fins of the heat exchanger cores, it coolsthe intake air. The cooling air then exits the front of the RATAAC assembly through two ducts(one on each side) that direct the cooling air out through the outlets at the upper left and upperright of the radiator guard.

The RATAAC system operation will be discussed in greater later in this presentation.


51

Cooling System

Shown above is a schematic of the cooling system for the D10T Track-type Tractor. The C27ACERT technology engine uses a Remote Air To Air AfterCooler (RATAAC) to cool the intakeair. The RATAAC is located beneath the hood and above the engine (not shown in the aboveillustration).

The AMOCS radiator contains twelve cores that are the standard "two-pass" type cores. Thehydraulic demand fan is mounted in front of the radiator and is controlled by the Engine ECM.This arrangement draws air in from the sides and/or the top of the engine compartment, throughthe radiator, and out the front of the tractor. This arrangement reduces the possibility of the fanejecting debris into the radiator cores.

Coolant flows from the water pump through the power train and engine oil coolers, then to theengine block. Coolant then flows through the engine block and into the cylinder heads. Fromthe cylinder heads, the coolant flows to the temperature regulators (thermostats) and either goesdirectly to the water pump through the bypass tube or to the radiator, depending on thetemperature of the coolant. If the thermostats are open, the hot coolant enters the bottom of theradiator and flows up through the front side of the cores, then down the back side of the cores.


Radiator

Jacket WaterPump

HydraulicOil Cooler

ThermostatHousing

Engine Oil Cooler

Power Train Oil Cooler 1

Power Train Oil Cooler 2

CabHeater

Turbo

Vent Line

Hottest

Coldest

IncreasingCoolant

Temperature

> 92 C

< 82 C

87 C

ShuntTank

C27 Engine

Turbo

D10T COOLING SYSTEMENGINE AT OPERATING TEMPERATURE

The coolant exits the radiator at the bottom through two outlets. Some of the coolant passesthrough the hydraulic oil cooler and some of the coolant bypasses the hydraulic oil cooler.These two flows combine after the hydraulic oil cooler and return to the jacket water pump.

A small amount of coolant flows to the turbochargers, which is used to cool the bearings, and isthen directed to the shunt tank. Coolant from the shunt tank is directed to the water pump.

The air vent lines allow air to escape from the cooling system while the system is being filledand during operation. The vent lines also aid in draining the system by eliminating any vacuumin the system caused by draining.

The shunt tank is a reservoir which retains the expansion volume of the coolant as the coolanttemperature increases. The level of the coolant in the shunt tank will rise as the coolanttemperature increases. The coolant level in the shunt tank will fall as the temperature of thecoolant decreases.

A drain valve (shown later) is present below the radiator and is used to drain coolant from theradiator cores, the engine oil cooler, the power train oil cooler, and the cab heater circuit.

NOTE: The thermostat housing for the C27 engine contains two thermostats. Theopening temperature for these thermostats is 81° - 84° C (178° - 183° F). Thethermostats should be fully open at 92° C (198° F).


The twelve AMOCS radiator cores (1) and the shunt tank (2) are shown above, from the rear ofthe radiator guard.

Hot coolant enters the radiator at the inlet tube (4), at the bottom left of the radiator. The hotcoolant flows up through the front side of the AMOCS cores, then down the back side, passingtwice through the cores. The hydraulic oil cooler (3) is located beneath the radiator guard.Some of the coolant exits the radiator through the cooler inlet bonnet (5) and flows through the"oil-to-water" type hydraulic oil cooler. The remainder of the coolant exits the radiator throughthe radiator outlet bonnet (6) where it mixes with the coolant from the hydraulic oil cooler. Thecombined coolant flow exits the bonnet through the outlet tube (7) and returns to the waterpump. The coolant drain line from the engine oil cooler and power train oil coolers, and thecoolant drain line from the engine block all connect to the fittings (8). This allows coolant to bedrained from the entire system through the radiator drain valve (9).

52

53


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89

The fan (1) and the hydraulic fan motor (2) may be accessed by opening the grill doors on thefront of the radiator guard, as shown in illustration No. 54. The hydraulic demand fan pump ismounted to the rear of the engine flywheel housing, at the upper left corner of the housing. (Thehydraulic demand fan system will be discussed in greater detail later in this presentation.) Airthat passes through the RATAAC heat exchanger cores exits the front of the tractor through thetwo openings (3) at the upper left and right of the radiator guard.

The radiator fill cap (4) and coolant level sight glass (5) are located under the spring-hinged door (6) on top of the hood, at the front, left. The coolant sight glass (5) is installed in thecoolant shunt tank and is visible when the access door is opened. If coolant is visible in thesight glass, it is at or above the ADD mark in the tank. If there is no coolant showing in thesight glass, coolant should be added until coolant is visible in the sight glass.

54

55


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56

Hydraulic Demand Fan System

The hydraulic demand fan is standard on the D10T Track-type Tractor. The fan is part of thehydraulic system, but it is controlled by the Engine ECM. The Engine ECM considers twoinputs for controlling the fan.

The engine coolant temperature sensor provides temperature information to the Engine ECM.The Engine ECM constantly monitors this temperature input. The fan pump discharge pressuresensor is the second input to the Engine ECM. Fan pump discharge pressure is controlled by theEngine ECM. Fan speed is determined by fan system pressure.

The Engine ECM monitors the temperature input and also considers fan pump dischargepressure to provide a signal to the (proportional) fan pump pressure control solenoid. Maximumflow is sent to the fan motor, causing the fan to turn at the maximum controlled rpm, when thesolenoid receives minimum current from the Engine ECM. Maximum mechanical pumppressure (high pressure cutoff) can be achieved by disconnecting the electrical connection to thesolenoid or by using Cat ET to turn OFF the fan control (Engine ECM/Configuration screen).


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Illustration No. 56 shows a schematic of the standard hydraulic demand fan system with the fansystem at maximum controlled pressure, resulting in maximum controlled fan speed.

When maximum fan speed is required, the fan pump pressure control solenoid is de-energizedaccording to the temperature input, causing the fan to turn at a faster speed. Maximumcontrolled fan speed is attained when the fan pump pressure control solenoid receives the leastamount of current from the Engine ECM.

If communication is lost between the Engine ECM and the fan pump pressure control solenoid,the fan will default to the maximum mechanical pressure setting (high pressure cutoff). Thisresults in a higher system pressure and fan speed than the maximum controlled pressure andspeed.

Cat ET may be used to reset the maximum controlled fan system pressure (from the maximumpressure set at the factory). This adjustment may be necessary to correct the maximumcontrolled fan speed due to differences in the initial factory settings and the tractor's currentworking environment. The Systems Operation Test and Adjust manual for the D10T hydraulicsystem (Form No. RENR7545) provides details of the fan speed/pressure adjustment procedure.

After the correct pressures have been verified for the minimum controlled fan pump pressureand the maximum mechanical fan pump pressure (high pressure cutoff), a photo-tachometermust be used to determine the fan speed at a given pressure. If the fan speed is not within thespecification at the given pressure, Cat ET must be used to override the pump control solenoiduntil the correct fan speed is attained. The pressure observed at the correct fan speed must thenbe entered and saved to the Engine ECM (Clip Pressure, found in the Engine Configurationscreen). The new clip pressure then becomes the target pressure that the Engine ECM seeksunder the maximum controlled fan system pressure condition.

In cooler weather, the Engine ECM may utilize an engine software strategy called "Cool EngineElevated Idle Strategy" when the following conditions are met:

- Coolant Temperature is less than 70°C (158°F)- Parking brake is set to ON- Transmission is in NEUTRAL- Throttle switch is set to LOW IDLE

Under these conditions, the Engine ECM will automatically increase engine speed, up to 1100 rpm, in an effort to increase coolant temperature. This strategy is ignored when any of thefour conditions are not met.

NOTE: Refer to the Hydraulic Schematic Color Code chart at the end of thispresentation to interpret the meaning of each color/pattern in the schematic.


57

Shown above is a schematic of the D10T standard hydraulic demand fan system with the fan atminimum speed.

The fan pump pressure control solenoid is energized, causing the fan to turn at a slower speed ifmaximum fan speed is not required. Minimum fan speed is attained when the fan pumppressure control solenoid is completely energized.

When the fan pump pressure control solenoid is completely energized, the pressure control spoolis unseated by the solenoid, allowing pump pressure to drain to tank. This action lowers thepressure in the spring chamber of the pump control spool and the pump control spool shifts up.Pump flow is then allowed to fill and pressurize the large actuator in the fan pump and the pumpdestrokes. With the pump destroked, oil flow to the fan motor is reduced and the fan speed isreduced.

The fan will default to the maximum mechanical pressure setting if communication is lostbetween the Engine ECM and the fan pump pressure control solenoid. This results in a fanspeed that is higher than the maximum controlled fan speed.


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The Engine ECM de-energizes the fan pump pressure control solenoid, sending the least amountof current when conditions require maximum controlled fan speed. (With no current, themechanical high pressure cutoff will raise the fan speed to its absolute maximum rpm. Thisstate can be achieved by disconnecting the fan pump control solenoid or by using Cat ET to turnfan control OFF. This procedure is required when making adjustments to the fan systempressure settings.)

The pressure control spool spring forces the top half of the pressure control spool up, against thesolenoid pin and holds the land of the upper pressure control spool against the seat when thesolenoid receives minimum signal. This blocks most of the pump output oil in the pump controlspool spring chamber from draining to tank through the case drain passage, which causes thepump control spool spring chamber to become pressurized. The force of the spring at the top ofthe pump control spool, plus the pressure of the oil, is then greater than the oil pressure at thebottom of the pump control spool. The pump control spool is held down, blocking pump outputoil from entering the signal passage to the large actuator piston in the pump. The large actuatorpiston is then open to drain and is at tank pressure.


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The bias spring moves the pump swashplate to an increased angle, which causes the pump toUPSTROKE when only tank pressure is present in the large actuator piston. This conditionprovides a controlled maximum flow of oil to the fan motor and creates maximum controlled fanpump system pressure, which results in maximum controlled fan speed.

The solenoid pin does not force the top half of the pressure control spool down against thespring if the solenoid fails (no current to the solenoid). This condition causes the pressurecontrol spool to be completely seated. Pump pressure will then increase until the upper half ofthe pressure control spool is forced down by oil pressure, against the force of the pressurecontrol spool spring. The oil in the pump control spool spring chamber can then flow past theupper control spool and drain to tank through the case drain passage. This lowers the pressurein the pump control spool spring chamber. The force of the spring at the top of the pump controlspool plus the pressure of the oil in the pump control spool spring chamber is now less than theoil pressure at the bottom of the pump control spool, due to the orifice effect of the passagethrough the pump control spool. The higher pressure at the bottom of the pump control spoolforces the spool up, allowing pump output oil to enter the signal passage. This causes pressurein the pump's large actuator piston to increase.

The increased pressure in the large actuator piston overcomes the pressure in the pump's smallactuator plus the force of the pump bias spring. This causes the swashplate to move to adecreased angle and the pump DESTROKES until a balance is attained in the pressures. Thiscondition results in mechanical high pressure cutoff. The pump then provides maximum flow tothe fan motor, resulting in a higher fan pump system pressure than that allowed by the control ofthe Engine ECM. The fan motor will then turn at its highest speed, which is higher than themaximum controlled fan speed.

The mechanical high pressure cutoff is adjusted using the adjustment screw. When theadjustment screw is turned in (clockwise), it increases the force of the pressure control spoolspring, which increases the the pump pressure required to unseat the land of the upper pumpcontrol spool, thereby increasing maximum cutoff pressure.

Maximum cutoff pressure will be lowered when the screw is turned out (counter-clockwise).


59

The Engine ECM energizes the fan pump pressure control solenoid (proportional to the coolanttemperature sensor signal) when a slower fan speed is required.

The solenoid pin pushes down on the upper half of the pressure control spool when the solenoidis energized. This unseats the spool against the force of the pressure control spool spring,allowing oil in the pump control spool spring chamber to drain to tank through the case drainpassage. This lowers the pressure in the pump control spool spring chamber. The force of thespring at the top of the pump control spool plus the pressure of the oil in the pump control spoolspring chamber is now less than the oil pressure at the bottom of the spool, due to the orificeeffect of the passage through the pump control spool. The higher pressure beneath the pumpcontrol spool then forces the spool up, allowing pump output oil to enter the signal passage.This causes pressure in the pump's large actuator piston to increase.

The increased pressure in the large actuator piston overcomes the oil pressure in the pump'ssmall actuator plus the force of the pump bias spring. This causes the swashplate to move to adecreased angle, and the pump DESTROKES. The pump then provides less flow to the fanmotor, resulting in lower fan pump system pressure and a slower fan speed.


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Illustration No. 59 shows the fan pump swashplate at minimum angle, which produces minimumflow. This will cause the fan motor to turn at its slowest speed.

Refer to RENR7545, "Systems Operation/Testing and Adjusting - D10T Track-type TractorHydraulic System" for information regarding the adjustment of the hydraulic demand fan.


60

A combination fan reversing/bypass valve will be installed on the bottom plate of the radiatorguard, at the lower right, if the machine is equipped with either the reversing fan feature or thefan bypass feature. A bi-directional fan motor will replace the standard fan motor with thereversing fan feature. The valve body contains all of the components for either feature,regardless of which way the demand fan system is configured. The software (flash file)contained in the Engine ECM contains the code that activates either strategy.

The Engine ECM will automatically activate the fan reversing solenoid valve at pre-determinedintervals, if the machine is equipped with the optional reversing fan. Fan reversing intervals andreversing duration may be re-configured using Cat ET. The fan may also be reversed manuallyusing the manual fan reversing switch, which is located below the Advisor display panel in theoperator compartment.

The combination fan reversing/bypass valve contains the following components:- Fan Bypass Solenoid Valve - The Engine ECM will energize the fan bypass solenoid

valve when cold weather requires fan speeds lower than the minimum fan speed of thestandard fan strategy. The solenoid valve opens and allows most of the oil to bypass thefan circuit. Most of the oil then flows directly to the hydraulic oil cooler. Some of the oilstill flows to the fan motor, but the fan turns slowly and the cooling effect of the fan isextremely low.


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- Fan Reversing Solenoid Valve - The fan reversing solenoid valve is DE-ENERGIZEDwhen the system is in the normal, or fan forward condition. When the Engine ECMenergizes the fan reversing solenoid valve, some of the fan pump output oil is directed bythe solenoid valve to the pilot operated reversing valves. This action shifts the reversingvalves, which reverses the flow of oil to and from the fan motor, which results in drivingthe bi-directional fan motor in the reverse direction.

- Pilot Operated Reversing Valves - The pilot operated reversing valves are shifted by fanpump oil when the fan reversing solenoid valve is ENERGIZED. When the reversingvalves are shifted, they reverse the flow of pump oil to and from the fan motor.

- Crossover Relief Valves - The momentum of the fan prevents the fan motor fromimmediate directional change when the fan is first commanded to change directions (eitherreverse or forward). One of the crossover relief valves will open to help dissipate excesspressure during the directional change. The crossover relief valves also serve as anti-cavitation valves when the engine is shut down and the momentum of the fan continues todrive the fan motor. (In either case, the crossover relief valve that opens is dependent onthe direction of oil flow in the system.)

- Relief Valve - The relief valve opens momentarily whenever there are any pressure spikesin the system. The relief valve also opens when the fan is first commanded to changedirections (either reverse or forward). The momentum of the fan prevents the fan motorfrom immediate directional change when the flow of oil is reversed. The relief valve helpsdissipate excess pressure that may damage the system during a directional change.

Illustration No. 60 shows the fan hydraulic system with the reversing/bypass valve installed inthe demand fan hydraulic system, with the fan at maximum controlled speed and neither the fanreversing function nor the fan bypass function activated.

A reversing fan is standard on landfill machines and some other special applications. It mayalso be added as an attachment to a machine with a standard demand fan system.

The fan bypass feature is standard on all machines that are equipped with the cold weatherarrangement.


61

Illustration No. 61 shows the fan hydraulic system with the fan reversing function activated.Either a command from the Engine ECM or the operator activating the manual fan reversingswitch will energize the fan reversing solenoid valve. Supply oil is directed to shift the two pilotoperated reversing valves when the solenoid valve is ENERGIZED. This action reverses theflow of oil to and from the fan motor. The fan will then reverse direction, causing air to flow inthe from front to rear through the radiator.

During a fan motor directional change, pump flow has been redirected and conflicts with theflow of oil from the outlet port of the fan motor (due to the momentum of the fan and the"pumping effect" of the motor). The lower crossover relief valve will open during the transitionfrom forward to reverse until the fan has changed direction and has attained most of the targetspeed. Excess oil flow is directed back to the (new) tank passage when the crossover reliefvalve is open. The upper crossover relief valve performs the same function when the flow of oilchanges from reverse to forward.

The Engine ECM software determines when it is time for the fan to reverse direction. TheEngine ECM will energize the reversing valve solenoid only when the transmission is shifted toreverse. This strategy helps lessen the chance that any material spilling over the top of the dozerblade will be ejected into the fan blades and/or into the radiator cores, minimizing the potentialfor damage to the fan blades and the radiator fins.


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62

The illustration above shows the fan hydraulic system with minimum oil flow and the fanbypass function activated. The Engine ECM will ENERGIZE the fan bypass solenoid valvewhen the temperature conditions specified in the software (flash file) have been met.

Most of the oil flow from the fan pump is directed back to tank when the fan bypass solenoid isenergized. Some oil still flows to the fan motor, but the fan turns at a greatly reduced rpm that isbelow the minimum fan speed of the standard fan system.

The fan bypass strategy results in minimal air to flow through the radiator.


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The hydraulic demand fan pump (1) is mounted at the upper left of of the flywheel housing.Shown above is the pressure test port for Hydraulic Demand Fan Pump discharge pressure(HDFP) (2), the fan pump pressure sensor (3), the pump pressure control spool adjustment screw (4), the pump control spool adjustment screw (5), and the fan pump pressure controlsolenoid (6). The drive hub (7) at the rear of the fan pump is connected to a drive shaft for thepower train oil pump.

The hydraulic demand fan motor (8) is mounted to a bracket at the front of the radiator guard.Shown in illustration No. 64 is the fan motor case drain line (10), and the fan motor inlet andoutlet ports (9).

The status of the fan pump pressure sensor may be viewed through the Advisor panel(Service/System Status/Engine screens) or by using Cat ET.

63

64


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The combination fan reversing/bypass valve (1) is mounted on top of the bottom plate of theradiator guard, at the right side if the machine is equipped with a reversing fan or if it isequipped for cold weather. It may be accessed through the front grill doors on the radiatorguard.

Service points on the fan reversing/bypass valve shown here are:

2. the pilot operated reversing (diverter) valve (the other reversing valve is located on theother side of the valve body)

3. the two crossover relief valves

4. fan pump supply lines to/from the fan motor (the supply lines to/from the valve areconnected beneath the valve)

5. fan reversing solenoid valve

6. fan bypass solenoid valve

7. check valves

The status of the fan reversing solenoid and the fan bypass solenoid may be viewed through theAdvisor panel (Service/System Status/Engine screens) or by using Cat ET.

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66

Remote Air To Air AfterCooler System

The Remote Air To Air AfterCooler (RATAAC) system provides cooled air to the engine intakemanifold. Air is drawn in through the pre-cleaner and the twin air filters by the turbochargers.The turbochargers compress the air and force it through the RATAAC heat exchanger cores.From the heat exchanger cores, the air flows into the intake manifold. The RATAAC heatexchangers cool the intake air that passes through them.

A hydraulic fan in the RATAAC draws air in through a separate pre-cleaner and distributes theair evenly over the heat exchangers to cool the intake air. The air passing over the heatexchangers is vented to the outside through air ducts located at the upper left and right cornersof the radiator guard.

The RATAAC fan motor and fan shaft bearings have been redesigned in the D10T to improvedurability and to reduce noise levels. The bearings are lubricated with case drain oil from theRATAAC hydraulic motor.

The RATAAC fan motor is driven by hydraulic oil supplied from the rear (small) section of theimplement pump. The rear section also supplies oil to the pressure reducing manifold and pilotsupply oil to the dual tilt valve.


RATAACFan

Small Pumpfor RATAAC Fanand Pilot Supply

SequencerValve

To PressureReducingManifold HFMI

HFPD

RATAAC Fan SpeedControl Valve

ReliefValve

Accumulator

To CaseDrain

D10T RATAAC FAN CIRCUIT

Illustration No. 66 shows the hydraulic circuit for the RATAAC fan system. Oil from the small(rear) hydraulic pump enters the RATAAC fan speed control valve where the sequencer valveensures that a sufficient supply of oil is first available to the pressure reducing manifold. Thepressure reducing manifold supply has priority over the RATAAC supply. The sequencer valvemaintains a minimum oil pressure to the pressure reducing manifold.

The relief valve is installed to limit the maximum RATAAC fan system pressure and themaximum RATAAC fan speed. The relief valve is pilot operated. Oil enters the left end of therelief valve and the pressure moves the spool to the right, against the spring. At the same time,oil flows through an orificed passage in the center of the spool and acts against the right end ofthe spool. The reduced oil pressure plus the force of the spring at the right end of the spoolbalances against the pressure at the left end of the spool. The result is a constant pressure in thefan system, proportional to the engine rpm. Oil that is drained by the relief valve returns to thehydraulic tank.

The accumulator helps maintain a constant system pressure when there are pressure fluctuationsin the fan circuit. The accumulator also serves as a "shock absorber" for the system duringpressure spikes.

INSTRUCTOR NOTE: During lab exercises, the following pressures may be observed:

- The sequencer valve is adjusted at low idle and the pressure observed (HFPD) should beapproximately 4068 kPa (590 psi). At high idle, the pressure observed should beapproximately 5860 kPa (850 psi). (Note that once the sequencer valve opens, atapproximately 4068 kPa (590 psi), the pressure in the small pump circuit is then controlledby the relief valve for fan system pressure.)

- The relief valve for fan system pressure is adjusted at high idle and the pressure observed(HFMI) should be approximately 5690 kPa (825 psi). The RATAAC fan speed at high idleshould be approximately 3100 rpm.

Always refer to the latest revision of the Service Manual for your machine serial number,"Specifications, Systems Operation, Testing and Adjusting - Hydraulic System" (FormNo. RENR7540) for the most recent specifications of system pressures.


The RATAAC components are mounted to the under side of the hood. These components are:

1. air intake and pre-cleaner for the RATAAC (cooling air)2. air intake and pre-cleaner for engine intake air (cooled air)3. left and right exhaust pipes (with ejector tubes)4. left and right muffler inlets5. dust ejector hoses (connecting the pre-cleaners to the dust ejector tubes in exhaust pipes)6. intake air tubes to air cleaner canister inlets (from RATAAC air pre-cleaner)7. RATAAC heat exchanger core outlets (cooled intake air to intake manifold)8. RATAAC heat exchanger core inlets (from air cleaners)

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The illustration above shows the RATAAC sub-assembly (upside down). The majorcomponents identified are:

1. RATAAC hydraulic fan motor

2. dust ejector tubes (from pre-cleaner to exhaust pipe)

3. heat exchanger cores

The heat exchanger core access panels (4) are removed in the illustration above. The cores maybe accessed and cleaned through these passages.

Refer to the D10T Operation and Maintenance Manual (Form No. SEBU7764) for informationabout recommendations for cleaning the RATAAC heat exchanger cores.

69

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Shown above is the implement pump. The rear section of the implement pump (1) provideshigh pressure oil for the RATAAC fan motor and for pilot supply to the pressure reducing valveand the dual tilt valve. Attached to the pump is the RATAAC fan speed control valve (2).Components and service points identified above are:

3. Hydraulic Fan Pump Discharge pressure test port (HFPD)

4. Hydraulic Fan Motor Inlet pressure test port (HFMI)

5. RATAAC fan motor supply

6. sequencer valve (ensures that pilot supply has priority over RATAAC supply)

7. relief valve (limits the maximum pressure in the RATAAC circuit)

8. relief to tank

9. accumulator (ensures continuous RATAAC circuit pressure and protects against surges)

10. supply to the pilot manifold

NOTE: The fitting for dual tilt pilot supply oil is on the front side of the manifold,beneath the fan supply line. It cannot be seen in the illustration, above.


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71

POWER TRAIN

Shown above is an illustration that identifies the relative location of all of the major power traincomponents for the D10T Track-type Tractor. Numerous upgrades have been implemented in thepower train for the D10T Track-type Tractor, as compared to the D10R machine. The mostprominent of these upgrades include:

- the torque converter impeller has been re-engineered to provide slightly more engine lug;

- the elimination of the transmission intermediate speed sensors;

- transmission output speed sensors that are more easily installed and require no adjustment;

- the elimination of the priority valve and the lube management valve simplifies the system,making it more reliable and easier to service and troubleshoot;

- a new A4 Power Train ECM controls the transmission, the braking, and the steering;

- a new four-section power train oil pump;

- easy access to two, 6-micron power train oil filters; and

- extended change intervals for power train oil filters.


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Power Train Electronic Control System

The illustration above is a simplified schematic that shows all of the major hydraulic componentsand all of the major electronic components in the power train system.

The Power Train Electronic Control System consists of the Power Train ECM and all the inputs toand outputs from the Power Train ECM. The Power Train ECM and its software considers theinput information, such as the service brake pedal position sensor, and controls the power trainoutput components, such as the electronic steering clutch and brake control valve.

The Power Train ECM will update the Caterpillar Monitoring and Display System if any of thecontrols or components are operating improperly or performing outside their operatingparameters. Advisor will then warn the operator or serviceman of the specific abnormalcondition.

Refer to STMG 790, "Caterpillar Monitoring and Display System, with Advisor™ for Track-typeTractors" (SERV1790) for more information and instructions for:

- accessing and viewing the status of the power train components;- how to change the parameters or the power train configuration; and/or- how to perform calibrations for any of the power train components.


TorqueDivider

Torque ConverterOutlet Relief Valve

Torque ConverterInlet Relief Valve

Lube DistributionManifold

TransmissionCharging Filter

To Clutch / Brake andTransmission Lube

Torque ConverterCharging Filter

Power TrainOil Coolers

Right SteeringClutch and Brake

Parking Brake Switch

Power Train ECM

TransmissionModulating Valves

Main Relief Valve

Service BrakePedal

Advisor

Power TrainInputs/ Outputs

CAT Data LinkData Port

TransmissionControls

Engine ECM

FTC

Left SteeringClutch and Brake

ElectronicSteering Clutchand Brake Valve

Parking andSecondaryBrake Valve

Primary (Crankshaft)Speed / Timing Sensor

Instrument Cluster

2.3 1F132.1

CAN CData Link

CAN AData Link

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D10T POWER TRAIN ELECTRONIC CONTROL SYSTEM

73

Power Train Hydraulic System

The four-section fixed displacement power train oil pump is installed at the left front of the maincase. The pump is driven by a drive shaft connected to the rear of the demand fan pump.

At high idle, the transmission and torque converter charging section "D" of the power train oilpump supplies approximately 190 L/min (50.2 gpm) of power train to the transmission hydrauliccontrol and to the electronic steering and brake control valve.

The transmission main relief valve maintains the correct pressure for operation of thetransmission modulating valves and for operation of the electronic steering and brake controlvalve.

The transmission clutches, the steering clutches, and the brakes operate at the same pressure,due to the common top pressure power train strategy. Transmission clutch engagement pressurecalibrations and brake pressure adjustments are not required. (Transmission clutch fill timecalibrations, steering clutch high pressure calibrations, and brake touch-up calibrations are stillrequired.) Correct oil pressure is available for the operation of the transmission clutches, thesteering clutches, and the brakes when the transmission main relief valve is properly adjusted.


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At high idle, the torque converter charging section "C" of the power train oil pump drawsapproximately 140 L/min (37 gpm) of power train oil to the torque converter, through the torqueconverter inlet relief valve. Oil from the transmission and torque converter charging section ofthe power train oil pump that flows past the main relief valve mixes with the torque convertercharge oil. The two oil flows mix inside the torque converter inlet relief valve. The torqueconverter inlet relief valve limits the maximum oil pressure to the torque converter.

The torque converter outlet relief valve maintains the minimum pressure inside the torqueconverter. Oil that exits the torque converter through the torque converter outlet relief valve isdirected to the power train oil coolers. Oil that exits the power train oil coolers is then sent tothe lube distribution manifold. The lube distribution manifold provides cooled lube oil to thetransmission, the bevel gears, and the steering clutches and brakes.

The torque converter scavenge section "B" of the power train oil pump draws oil from the torqueconverter housing through a screened port. This oil is then directed back to the main sump. Thetorque converter scavenge section draws approximately 20 L/min (5.3 gpm) of oil at high idle.

The transmission scavenge section "A" of the power train oil pump draws oil from thetransmission and bevel gear case through a screened port. This oil is directed to the lubedistribution manifold where it mixes with the oil from the power train oil coolers. Thecombined oils are used to lubricate the transmission and bevel gears and the steering clutchesand brakes.

Transmission pump pressure (TP), transmission main relief pressure (P), torque convertersupply pressure (M), transmission lube pressure (L1), and the power train oil fluid sampling(S•O•S) port are all easily accessible from the rear of the machine. All of the other power trainpressure test ports must be accessed through the floor plates in the operator's compartment.

INSTRUCTOR NOTE: It should be noted that the D10T no longer uses a priorityvalve.

NOTE: Refer to the Hydraulic Schematic Color Code chart at the end of thispresentation to interpret the meaning of each color/pattern in the schematic.


74

The torque converter inlet relief valve and the lube distribution manifold are mounted to theright front of the main case. They are consolidated into one housing (1).

The electronic steering and brake control valve (2) is mounted to the top of the main case.

The four-section power train oil pump (4) is driven by a shaft that connects the drive hub (3) to adrive hub on the rear of the hydraulic demand fan pump (not pictured). The drive shaft iscovered by a guard when the machine is completely assembled.

The transmission charging section and the torque converter charging section of the power trainoil pump (4) draw their oil from the main sump through the screened suction manifold (5). Thesuction screen is accessible for cleaning by removing the cover (6) on the front of the suctionmanifold.

The vent line (7) connects the torque converter housing and the main case to maintain an equalatmospheric pressure inside both components. The power train breather is remotely mounted inthe compartment at the rear of the left fender. The remote line for the breather (not yet installedin the illustration, above) connects to the vent line with a "tee" fitting.


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The four-section, fixed displacement power train oil pump is mounted to the left, front of themain case. This fixed displacement gear pump consists of:

1. transmission and torque converter charging section "D"2. torque converter charging section "C"3. torque converter scavenge section "B"4. transmission scavenge section "A"

The pump drive hub (5) connects to a shaft that is driven by the hub at the rear of the hydraulicdemand fan pump (shown earlier in this presentation).

Other power train components shown in the illustration above are:

6. transmission oil fill tube7. transmission oil dipstick tube8. screened main sump suction manifold9. access cover to the main sump suction screen


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The two, 6-micron power train oil filters are located at the rear of the machine. Shown in theillustration above is the torque converter charging filter (1) and the transmission charging filter (2).

The ecology drain (3) for the transmission case is also located at the rear of the machine, at thebottom of the transmission case.

The transmission hydraulic control, which contains the transmission modulating valves and thetransmission main relief valve, may be accessed by removing the transmission inspection cover(5), at the top of the transmission case.

The transmission output speed sensors may be accessed by removing the bolts from main coverfor the transmission case (4) and then sliding the transmission rearward, out of the transmissionand bevel gear case. (The four bolts that hold the transmission and bevel gear case to the maincase must remain.) This procedure allows access to the speed sensors without draining all of thepower train oil and without removing of the axles. Refer to the procedure for "TransmissionRemoval and Installation" in the D10T Power Train Disassembly and Assembly Manual (FormNo. RENR8166) for the details of this procedure.

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The transmission charging filter (1) is located at the upper left, rear of the main case. Servicepoints located on this filter base are:

2. power train filter oil filter bypass switch3. transmission controls temperature sensor4. transmission pump pressure test port (TP)

The torque converter charging filter (6) is located at the upper right, rear of the main case.Power train oil fluid samples (S•O•S) maybe taken from the test port (5), located on the rightside of the filter base.

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The transmission controls temperature sensor monitors the temperature of the power train oilfrom the main sump. This is the sensor that that is considered when using the Advisor panel orCat ET to perform power train calibration routines. This is also the sensor that provides thesignal for the "Transmission Oil Temperature" readout on the Advisor panel (Service/SystemStatus/Power Train screens).

The power train oil filter bypass switch is a normally open pressure switch. The status of thepower train oil filter bypass switch may be viewed using the Advisor panel (Service/SystemStatus/Power Train screens) or by using Cat ET.



Located at the top of the transmission case are the following pressure test ports:

1. transmission main relief pressure (P)

2. torque converter supply pressure (M)

3. transmission lube pressure (L1)

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Power train oil exiting the torque converter passes through the power train oil coolers and thenflows through the hose at the left (1) and into the lube distribution manifold (4). Oil from thetransmission scavenge section of the power train oil pump is directed to the lube distributionmanifold through the steel tube (5), where it combines with the oil from the coolers. Thiscombined oil is used for lubrication purposes and is distributed to the left and right steeringclutches and brakes and to the transmission and bevel gears.

System lube pressure (L2) can be checked using the alternate lube system pressure tap (2)(partially hidden, above), on the right side of the manifold. The lube temperature sensor (3) isinstalled in the top of the lube distribution manifold.

Oil from the torque converter charge section of the power train oil pump flows through thetorque converter charge filter and then to the torque converter inlet relief valve (7) where itmixes with the oil that flows past the transmission main relief valve. Most of this oil is suppliedto the torque converter through the hose at the right (8). Relief oil from the torque converterinlet relief valve flows back into the main sump through a port (not visible) at the back of thehousing. Torque converter supply pressure (M1) can be tested at the alternate pressure tap (6)on the left side of the housing.


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The torque converter inlet relief valve protects the components in the torque converter bylimiting the maximum oil pressure to the torque converter during pressure spikes in the system.This valve also protects the torque converter components when the engine is started and the oilis cold.

Oil from the torque converter charging section of the power train oil pump is directed to thetorque converter inlet relief valve through a passage in the front of the main case. Transmissionand torque converter charge oil that flows past the transmission main relief valve combines withthe torque converter charge oil through another passage in the front of the main case. The twoflows combine in the valve body and then flow past the torque converter inlet relief valve to thetorque converter through a connecting hose.

Oil flows into the torque converter inlet relief valve through the inlet passage. The oil thenflows into the cross-drilled hole in the small diameter of the spool and through the centerpassage of the spool. The oil then flows through the center of the poppet and then into thechamber at the right end of the spool, pressurizing the chamber. When the oil pressure at theright end of the spool overcomes the force of the spring at the left end, the spool shifts to the leftand dumps the excess oil back into the main case through the tank passage. This limits thepressure in the torque converter circuit.


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The torque converter inlet relief valve is not adjustable. There is no adjustment screw for thetorque converter inlet relief valve. Do not add or remove shims.

The spring and/or the spool or other components must be replaced if the torque converter inletrelief valve is not operating properly.


82

Torque Divider

The D10T Track-type Tractor uses a torque divider (1) to transfer engine power to thetransmission. The torque divider is similar to those used on other Caterpillar Track-typeTractors.

The torque divider provides both a hydraulic and a mechanical connection from the engine tothe transmission. The torque converter provides the hydraulic connection, while the planetarygear set provides the mechanical connection. During operation, the planetary gear set and thetorque converter work together to provide an increase in torque as the load on the machineincreases.

The illustration above shows the torque divider used in the D10T. The torque converter outputspeed sensor (2) is installed above the torque divider output shaft (5) and senses the speed of theoutput shaft. The Power Train ECM monitors the signal from this sensor and uses it, along withthe signal from the engine primary (crankshaft) speed/timing sensor to determine engine lug andshifting points for the Auto KickDown strategies. This signal is also used as one of the inputs todetermine track speed, which is displayed on the LCD display in the instrument cluster.


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Torque converter charge oil from the torque converter inlet relief valve enters the torqueconverter through the torque converter inlet port (3), at the top of the torque divider housing.

A vent line between the torque converter housing and the main case installs at the fitting (4) nearthe top of the torque converter housing. A breather is installed on the vent line (remotelymounted inside the rear compartment on the left fender) to ensure that case pressures are equalto the atmospheric air pressure. The breather needs to be cleaned periodically.

The ecology drain valve for the torque divider housing (7) is located at the bottom of the torquedivider housing. It may be accessed through a plate in the bottom guard, directly below thedrain valve.

The scavenge section of the power train oil pump draws oil from the torque divider housingthrough the port (6) to the left of the ecology drain. The torque converter scavenge screen (notvisible) is located inside the hose flanges.

The torque converter outlet relief valve (8) is located on the right side of the torque dividerhousing.

The status of the torque converter output speed sensor may be viewed through the Advisor panel(Service/System Status/Power Train screens) or through Cat ET.


83

This illustration shows a typical torque divider as used in the D10T. The impeller, the rotatinghousing, and the sun gear are shown in red. These components are on a direct mechanicalconnection to the engine flywheel. The turbine and the ring gear, shown in blue, aremechanically connected. The planetary carrier and the output shaft, shown in purple, are alsomechanically connected. The stator and carrier are shown in green. The planetary gears andshafts are orange.

Because the sun gear and the impeller are connected to the flywheel, they will always rotate atengine speed. As the impeller rotates, it directs oil against the turbine blades, causing theturbine to rotate. Turbine rotation causes the ring gear to rotate. During NO LOAD conditions,the components of the planetary gear set rotate as a unit at the same rpm and the planet gears donot rotate on their shafts.

As the operator loads the machine, the output shaft slows down. A decrease in output shaftspeed causes the rpm of the planetary carrier to decrease. Decreasing the planetary carrierrotation causes the relative motion between the sun gear and the planet carrier to cause theplanet gears to rotate. Rotating the planet gears decreases the rpm of the ring gear and theturbine. At this point, the torque splits with the torque converter multiplying the torquehydraulically and the planetary gear set multiplying the torque mechanically.


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An extremely heavy load can stall the machine. If the machine stalls, the output shaft and theplanetary carrier will not rotate. This condition causes the ring gear and turbine to rotate in theopposite direction of engine rotation. Maximum torque multiplication is achieved just as thering gear and turbine begin to turn in the opposite direction.

The torque divider is also equipped with a freewheel stator. The stator is splined to a cam whichrotates around the stationary carrier in only one direction. Machined into the cam are taperedopenings, each of which contain a roller and a spring. Spring force holds the roller against thetaper and the carrier. This restricts the cam from turning.

When the machine is under a load, and the impeller and turbine are rotating at different speeds,the stator is held stationary. The stator directs oil flow to the impeller, multiplying the torque.

During all load conditions, the torque converter provides 70% of the output, and the planetarygear set provides the remaining 30% of the output.


84

The torque converter outlet relief valve (1) is installed at the right rear of the torque dividerhousing. Torque converter oil exiting the torque converter enters the torque converter outlet reliefvalve through the inlet passage in the valve body (1), where it connects to the outlet port of thetorque converter. The oil then exits the outlet relief valve at the valve outlet passage and is thendirected to the power train oil cooler through the upper steel tube (5). The cooled power train oilreturns from the coolers through the lower steel tube (6). The oil is then directed to the lubedistribution manifold through a hose that connects to the outlet (7) at the rear of the valve body.

Torque converter outlet relief pressure (N) can be tested at the left pressure test port (3). Coolerlube pressure (CL) can be tested at the right pressure test port (2).

The torque converter oil temperature sensor (4) is installed in the torque converter outlet reliefvalve. It senses the temperature of the power train oil exiting the torque converter and provides asignal to the Power Train ECM. Cat Advisor monitors this temperature data from the PowerTrain ECM and uses it to operate the torque converter oil temperature gauge (analog), located atthe upper right of the instrument cluster. The status of the torque converter oil temperature sensor(in degrees) may also be viewed through the Advisor panel (Service/System Status/Power Trainscreens and Performance 1 screen) or by using Cat ET.

Access to the torque converter outlet relief valve components is through the plate at the bottom ofthe valve body.


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85

The torque converter outlet relief valve maintains a constant minimum pressure inside the torqueconverter.

Oil from the torque converter enters the inlet of the torque converter outlet relief valve throughthe outlet passage of the torque converter. The pressure of the oil acts against the top of thespool. The spool shifts down when the pressure of the torque converter oil becomes greater thanthe force of the spring. Torque converter oil then flows through the holes around thecircumference of the spool to the outlet passage. The outlet passage directs the hot torqueconverter oil to the power train oil coolers.

The orificed passage that bypasses the valve spool increases the stability of the valve when thereare shocks to the system. This passage also helps ensure that a minimum amount of oil isalways available to the power train oil coolers, regardless of the state of the valve.

The torque converter outlet relief valve may be adjusted by adding or removing shims betweenthe spring and the spool.


Inlet Passagefrom

Torque Converter

Spool

Spring

Shims

Outlet Passageto Power Train

Oil Cooler

Orifice

Torque ConverterOutlet ReliefPressure Tap

D10T TORQUE CONVERTER OUTLET RELIEF VALVE

86

The D10T uses two power train oil coolers to cool the oil coming from the torque converter.The power train oil coolers are oil-to-water type oil coolers and are located along the right sideof the engine.

Hot power train oil exits the torque converter outlet relief valve and is directed to the powertrain oil coolers by the upper steel tube (1). Some of the oil passes through passage (2) into theNo. 1 power train oil cooler (3). The remainder of the oil enters the No. 2 power train oil cooler (4) at the forward inlet (5).

The oil is cooled as it passes front to rear through the oil-to-water type coolers. The cooled oilexits the No. 2 cooler through the cooler outlet (8), at the front of the cooler. Cooled oil exitsthe No. 1 cooler through the outlet (9) at the rear of the cooler, where it combines with the oilfrom the No. 2 cooler (10). The cooled oil returns to the front side of the torque converter outletrelief valve (see illustration No. 84) through the lower steel tube (11). The cooled oil is thendirected to the lube distribution manifold.

Engine coolant enters the power train oil coolers through the cast tubes (7) that are connected tothe water pump. The coolant exits the coolers through an outlet passages on the engine side (notvisible) where it is directed into the water jacket of the engine block.


1 2 3 45

6

7

8

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87

Power Shift Transmission

The planetary power shift transmission is capable of three speeds FORWARD and three speedsREVERSE. Power is transferred from the engine and the torque converter to the transmissionthrough the input shaft, which is inside the output shaft. Power is transferred from thetransmission to the transfer and bevel gears through the output shaft (1).

The transmission contains three hydraulically controlled speed clutches and two hydraulicallycontrolled directional clutches, which are located in the planetary group (2).

The Power Train Electronic Control System consists of the Power Train ECM and all the inputs toand outputs from the Power Train ECM. The transmission shifting function is controlled by thePower Train ECM.

The Power Train ECM receives signals from the upshift switch, the downshift switch, and/or theFNR direction lever position sensor when the operator requests a speed or directional change.The Power Train ECM responds to the shifting requests by controlling the electrical current to thesolenoids on the transmission modulating valves (4), located on the transmission hydraulic controlmanifold (3). The transmission modulating valves engage and disengage the transmissionclutches by controlling the flow of oil to and from the clutches. The Power Train ECM may alsomake automatic shift requests, if the AutoShift or the Auto KickDown functions are active.


1

2

3

4

The Power Train ECM uses the transmission speed, the engine speed, and the power train oiltemperature signals to control the smooth engagement of the clutches and a smooth transitionfrom one clutch to another clutch. Each transmission clutch in the planetary group has acorresponding transmission modulating valve located on the transmission hydraulic controlmanifold.

Electronic clutch modulation by the Power Train ECM controls the time required to fill a clutchwith oil. Clutch engagement pressure calibrations no longer need to be performed with the"common top pressure" power train strategy. Clutch fill time calibrations are still required. Theautomated clutch fill time calibration procedure can be performed using Cat Advisor or by usingCat ET. This calibration routine "teaches" the Power Train ECM the length of time required foreach clutch modulating valve to attain its clutch engagement pressure. The ECM applies currentto the solenoid until the transmission output speed sensors detect a slight movement of the outputshaft. When the output shaft begins to move, the ECM has "learned," and stored in its memory,the time required to pressurize the clutch to its engagement pressure.

NOTE: With the "common top pressure" strategy, clutch No. 1 (reverse direction), clutchNo. 2 (forward direction), clutch No. 3 (speed 3), and clutch No. 4 (speed 2) operate atmain relief pressure. The Power Train ECM sends approximately 1.0 amp of current tothese four transmission modulating valve solenoids to attain the clutch engagementpressure. Clutch No. 5 (speed 1) operates at a reduced pressure. The Power Train ECMregulates the pressure to the No. 5 clutch by sending a reduced current (approximately 0.7 - 0.8 amps) to the No. 5 transmission modulating valve solenoid.

NOTE: The Power Train ECM commands the transmission to 3rd speed/Neutral (No. 3clutch engaged and no directional clutch engagement) when the transmission is shifted toNEUTRAL.

The Power Train ECM constantly monitors the torque converter output speed and theengine speed. The Power Train ECM uses the pre-programmed speed maps (in thesoftware) to determine what the torque converter output speed should be, consideringpower train oil temperature and engine speed. If the Power Train ECM determines thatthe torque converter output speed is too low (torque load too high), the assumption is thatthe transmission is trying to move the machine (example: a directional clutch is trying tobe applied or is "dragging"). The Power Train ECM will then incorporate the "No ClutchNeutral" strategy under these conditions, and will automatically disengage clutch No. 3.The Power Train ECM will also ensure that the brakes are applied (proportional brakesolenoid is de-energized) if the power train oil is below 40°C (104°F).

This strategy is AUTOMATIC for the first 10 seconds after ANY start-up situation,regardless of power train oil temperature. If the operator releases the parking brake(switch OFF) within the first 10 seconds after start-up, the brakes will remain ENGAGEDindefinitely until the operator toggles the parking brake switch, requests a transmissionshift, or tries to steer the machine.


88

Transmission output speed and rotational direction is sensed by the two transmission outputspeed sensors (1). The speed/direction pick-up wheel (2) is splined to the transmission outputshaft (3). The wheel induces a current (signal) into each sensor as the speed/direction pick-upwheel moves past the sensors.

The difference in the timing between the signals of the two sensors determines the output shaftspeed. Output shaft rotational direction is determined by sensing which sensor provides a signalfirst. The signals from the sensors are monitored by the Power Train ECM. These signals areused by the Power Train Electronic Control System to modify the timing of clutch engagements.

The transmission output speed sensors do not require adjusting when they are installed. Theyare held in place with two clips, which maintain the proper air gap between the sensors and thespeed/direction pick-up wheel.

The status of transmission output speed sensors may be viewed through the Advisor panel(Service/System Status/Power Train screens) or by using Cat ET.


1

2

3

89

The transmission clutches are hydraulically engaged and spring released. The transmissionmodulating valve solenoids are energized to send transmission charge oil to the clutches, asshown in the illustration above. As current is applied to the solenoid, the pin extends to the rightand moves the ball closer to the orifice. The ball begins to restrict the amount of oil to drainthrough the orifice. This restriction causes the pressure to increase at the left end of the valvespool. As the pressure at the left end of the valve spool increases, the spool shifts to the rightagainst the spring, closing off the passage from the clutch to the drain. At the same time, themovement of the valve spool to the right opens the passage from the pump supply to the clutch.This causes the clutch pressure to increase.

De-energizing the solenoid decreases the force of the pin against the ball. This decreased forceallows the pressure at the left end of the valve spool to unseat the ball, de-pressurizing thechamber at the left end of the spool. With no pressure at the left end of the spool, the valvespool shifts to the left due to the spring force plus the supply oil pressure. This conditionreduces the pressure to the clutch by closing off the supply passage to the clutch and opening upthe drain passage. When the pressure to the clutch falls below the clutch engagement pressure,the clutches will be released by spring force.


BallValveSpool SpringOrifice

SolenoidPin

ToClutch

Supply Oilfrom Pump

TRANSMISSION MODULATING VALVEENERGIZED

When the transmission is in NEUTRAL, the transmission modulating valve that controlsengagement of the No. 3 clutch allows flow to the clutch. The other modulating valves stopflow to the clutches, thereby allowing the clutches to be released by spring force. Since neitherthe No. 1 nor the No. 2 directional clutches are engaged, no power is transmitted to the outputshaft of the transmission.

When the transmission is in FIRST SPEED FORWARD, the modulating valves that control flowto the No. 2 and the No. 5 clutches receive a signal from the Power Train ECM. This signalenergizes the solenoid which sends flow to engage the clutches.

The status of all five transmission modulating valve solenoids may be viewed through theAdvisor panel (Power Train System Status screens) or by using Cat ET.

NOTE: Clutch Engagement Pressure Calibrations are no longer necessary due to thecommon top pressure strategy. However, transmission Clutch Fill Time Calibrationsmust be performed when any of the following repair procedures have been performed:

-Transmission modulating valve and/or solenoid is replaced.

-Transmission is serviced or replaced.

-Power Train ECM is replaced.

Transmission Clutch Fill Time Calibrations may be performed using Cat Advisor or byusing Cat ET.


90

The transmission main relief valve is located in the transmission hydraulic control manifold.The manifold is on top of the transmission planetary group. The transmission main relief valvemaintains the "common top pressure" from the transmission charging section of the power trainoil pump. This oil is used to operate the brakes and the transmission clutches.

Oil to the main relief valve is supplied by the transmission charging section of the power trainoil pump, when the priority valve is in the Normal Mode. If the priority valve is in the PriorityMode, the oil supply to the transmission main relief valve is a mixture of transmission charge oiland torque converter charge oil.

Oil from the power train oil pump flows through the transmission charge oil filter and then tothe electronic brake control valve and the transmission modulating valves. The transmissionmain relief valve is downstream from the electronic brake control valve and the transmissionmodulating valves. The excess oil that flows over the main relief valve combines with the oilthat flows past the priority valve and supplies the torque converter inlet relief valve.


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91

The transmission main relief valve may be accessed by removing the transmission inspectioncover, which is located at the top of the main transmission cover. The transmission main reliefvalve is installed in the transmission hydraulic control manifold (1).

The transmission main relief valve may be adjusted by using the adjustment screw and locknut (2), at the right of the transmission hydraulic control manifold.

Each of the transmission clutch modulating valves (3) have a pressure test port installed on topof the valve body (see illustration No. 89). Individual clutch pressures may be tested byconnecting a hose and pressure gauge to the test port on the corresponding transmissionmodulating valve.


2

3

1

92

This visual shows a sectional view of a typical transmission group like that used in the D10TTrack-type Tractor. The planetary group has two directional and three speed clutches which arenumbered in sequence (1 through 5) from the rear of the transmission to the front. Clutches No. 1 and No. 2 are the reverse and forward directional clutches. Clutches No. 3, No. 4, and No. 5 are the third, second, and first speed clutches. The No. 5 clutch is a rotating clutch.

In this sectional view of the transmission, the input shaft and input sun gears are shown in red.The output shaft and output sun gears are blue. The ring gears are shown in green. Theplanetary carrier is brown. The planet gears and shafts are shown in orange. The clutch discs,the clutch plates, the pistons, the springs and the bearings are shown in yellow. The stationaryclutch housings are shown in gray.

The input sun gears are splined to the input shaft and drive the directional gear trains. Theoutput shaft is driven by output sun gears No. 3 and No. 4 and rotating clutch No. 5. When theNo. 2, No. 3, or No. 4 clutches are engaged, their respective ring gears are held stationary. TheNo. 1 planetary carrier is held when the No. 1 clutch is engaged. When engaged, the No. 5rotating clutch locks the output components (for FIRST gear) to the output shaft.


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93

Electronic Steering and Brake Control Valve

The electronic steering and brake control valve (1) is installed on the top of the main case, belowthe operator's seat. The steering and brake control valve may be accessed by removing theoperator seat, the seat pedestal, and the rear floor plate in the operator compartment.

The valve body contains four proportional solenoid valves that are controlled by the Power TrainECM. The Power Train ECM receives signals from the PWM rotary position sensors of the FTCsteering levers and from the PWM rotary position sensor that is connected to the service brakepedal. The right steering clutch solenoid (2), the right brake solenoid (3), the left brake solenoid(4), and the left steering clutch solenoid (5) are identified in illustration No. 93.

The brakes are spring applied and hydraulically released. The steering clutches are hydraulicallyapplied and spring released. The four proportional solenoids are normally ENERGIZED when thesteering clutches are engaged and the brakes are released. Pulling back on the left steering controllever begins to DECREASE the amount of current to the left steering clutch solenoid (5) and DE-ENERGIZES it. This begins releasing the left clutch and disengaging power to the left track.When the left steering control lever is pulled back to approximately one-half of the lever's traveldistance, the left steering clutch solenoid is completely DE-ENERGIZED and the left clutch iscompletely DISENGAGED. This results in a gradual left turn.


1

2 34

5

678

Pulling back further on the left steering control lever begins to DECREASE the amount of currentto the left brake solenoid (4) and DE-ENERGIZES it, to begin engaging the left brake. When theleft steering lever is pulled all the way to the rear, the left brake solenoid is completely DE-ENERGIZED and the left brake is completely ENGAGED, stopping the left track. This results in a sharp left turn.

Depressing the service brake pedal DECREASES the amount of current to both the left and theright brake solenoids and DE-ENERGIZES them to apply both the left and the right brakes.

The secondary brake valve is controlled by an ON/OFF solenoid (7). The ON/OFF solenoid isENERGIZED by connecting it to the battery when the secondary brake switch is activated. Thebrake switch is a part of the service brake pedal and it is activated near the end of travel of theservice brake pedal.

The parking brake valve is also controlled by an ON/OFF solenoid (6). The parking brakesolenoid is ENERGIZED by connecting the solenoid to the battery when the operator activates theparking brake switch. The steering clutch solenoids are also DE-ENERGIZED when the parkingbrake switch is activated. (The secondary brake valve solenoid is also ENERGIZED, along withthe parking brake valve solenoid when the parking brake switch is set to ON. This is a newparking brake backup strategy and is a change for this type of electronic brake control valve. Thisstrategy is used by all of the T-Series Track-type Tractors.)

The status of all four brake solenoids and the steering clutch solenoids may be viewed through theAdvisor panel (Service/System Status/Power Train screens) or by using Cat ET.

All four pressures for the steering clutches and the brakes (C1, B1, B2, C2) may be tested at thepressure test ports that are located on top, and at the rear of the brake control valve. The pressuretest port (8) for the right steering clutch (C1) can be seen in illustration No. 93. The other threepressure test ports correspond to the solenoids that are identified in the illustration.

INSTRUCTOR NOTE: The following information outlines the state of the four brakevalve solenoids in the three possible conditions for the service brakes (brake pedal):

Service Brakes Released- Proportional brake valve solenoids (L & R) - ENERGIZED- Parking brake valve solenoid - DE-ENERGIZED- Secondary brake valve solenoid - DE-ENERGIZED

Service Brakes Applied (full)- Proportional brake valve solenoids (L & R) - DE-ENERGIZED- Parking brake valve solenoid - DE-ENERGIZED- Secondary brake valve solenoid - ENERGIZED

Parking Brake Applied- Proportional brake valve solenoids (L & R) - DE-ENERGIZED- Parking brake valve solenoid - ENERGIZED- Secondary brake valve solenoid - ENERGIZED


94

The proportional solenoid valves for the steering clutches and the brakes are controlled by thePower Train ECM. The solenoid valves are ENERGIZED to engage the steering clutches and torelease the brakes. The Power Train ECM determines the amount of current sent to the solenoidby the position of the FTC steering control levers or by the position of the service brake pedal.

The explanation that follows describes the operation of the service brakes. This explanation,however applies to both the left and right brake circuits when the steering levers are used tocontrol the clutches and the brakes for steering. The steering clutches operate similarly, exceptthat the steering clutches do not use a shutoff valve or a shutoff spool in the valve body.

Hydraulic pressure is applied to release the brakes. Hydraulic pressure is applied to engage thesteering clutches.

When the proportional solenoid (valve) is ENERGIZED, the pilot valve is closed. This allowspump supply oil to pressurize the pilot pressure the chambers at the proportional solenoid valve,the parking brake valve and the secondary brake valve, and in the accumulator chamber. As theaccumulator chamber pressure increases, the reducing spool moves to the right against the spring,closing off the drain passage. At the same time, the passage to the brakes is opened to the passagefrom the pump supply oil. Pressure then builds in the pressure feedback chamber and in thepassage to the brakes. As the pressure increases, the spring applied brakes are released.


Supply Oil from Pump

ProportionalSolenoid Valve

AccumulatorPiston

Reducing Spool

Shutoff Valve

Parking BrakeSolenoid Valve

andSecondary Brake

Solenoid Valve

To BrakesPilot Pressure

Chamber

Orifice

Accumulator Chamber

Pressure FeedbackChamber

Parking / SecondaryBrake Valve

Pilot Valve

Slot Holes ShutoffSpool

Parking/SecondaryBrake Valve

Pilot Chamber

ELECTRONIC STEERING AND BRAKE CONTROL VALVEENGINE ON / BRAKES RELEASED

CheckValve

When the operator depresses the service brake pedal, the PWM sensor attached to the servicebrake pedal sends a signal to the Power Train ECM. The Power Train ECM then decreases thecurrent to the proportional solenoid at a rate that is directly proportional to the movement of thepedal.

As the solenoid is DE-ENERGIZED, the pilot valve opens and allows the pump supply oil in thepilot pressure chamber to drain to tank. This reduces the pressure in the pilot pressure chamberat the solenoid valve. The accumulator chamber and the parking/secondary brake valve pilotchamber are also reduced by draining oil through the holes in the shutoff spool.

As the pilot pressure at the left end of the shutoff spool decreases, the pilot pressure at the rightend of the shutoff spool moves the spool to the left, against the spring. When the spool movesall the way to the left, the holes in the spool are opened to drain due to the slot that is machinedin the shutoff valve. The pressures in the accumulator chamber and the parking/secondary brakevalve pilot chamber are now allowed to drain through the holes in the spool. As the pilotpressure decreases, the spring begins to move the shutoff spool back to the right.

As the shutoff spool moves back to the right, the holes in the spool are covered again by theright end of the shutoff valve. This reduces the rate of reduction in pilot pressure, allowing thebrakes to be slowly applied. The pilot oil can then only escape by flowing between the outerdiameter of the shutoff spool and the inner diameter of the shutoff valve, and then through theholes in the shutoff spool. As the pilot pressure slowly decreases, the spring moves the shutoffspool further to the right until the holes in the spool are uncovered again at the right end of theshutoff valve. The remainder of the pilot pressure then completely drains to tank through theshutoff spool.

As the pilot pressure decreases, the combined force of the reducing spool spring and thepressure in the feedback chamber moves the reducing spool to the left. The accumulator pistonacts as a cushion and aids in preventing the reducing spool from moving too rapidly.

As the reducing spool moves to the left, the pump oil supply passage to the reducing spool isclosed off. At the same time, the tank passage to the reducing spool is opened, allowing thepressure oil in the brakes to drain to tank. As the pressure to the brakes decreases, the Belvillesprings begin to engage the brakes.

If the operator depresses the service brake pedal completely, the secondary brake switch isactivated. The secondary brake switch makes a direct connection between the battery and thesecondary brake valve solenoid, which ENERGIZES the secondary brake solenoid. When thesecondary brake solenoid is energized, all the oil in the brake circuits is drained and the brakesare applied.


When the parking brake switch is set to the ON position, the parking brake valve solenoid isconnected directly to the battery, which ENERGIZES the parking brake solenoid. Thesecondary brake solenoid is also ENERGIZED by the battery when the parking brake switch isset to the ON position as a backup measure. Again, all the oil is drained and the brakes areapplied.

Energizing either of the solenoids for the parking brake valve or the secondary brake valvecompletely drains all pilot pressure oil, resulting in all of the oil being drained from the brakes.The brakes are then fully engaged.

NOTE: The check valves that are installed in the valve body between the reducingspools and the pressure chamber for the parking brake and the secondary brake valvesare only present on FTC machines. They serve to isolate the left brake circuit and theright brake circuit from each other, for steering purposes. The check valves allow onebrake circuit to be depressurized while maintaining the brake pressure in the other brakecircuit. The brake valve used on differential steer machines operates the same way, butthe check valves are not present because the brakes are not used for steering andtherefore, need not isolate the left and right brake circuits.


95

The illustration above, and those on the next few pages, show the electronic steering and brakecontrol valve as if it had been sliced in half, horizontally, with the upper half laid over to the top.The external lines in the illustrations represent the internal passages of the steering and brakecontrol valve as they would normally be connected.

Illustration 95 shows the electronic steering and brake control valve in the STRAIGHTTRAVEL, or NO STEER condition. Both brakes are DISENGAGED and the steering clutchesare fully ENGAGED.

When the service brake pedal is released and neither FTC steering control lever is movedrearward, the rotary position sensors (connected to the brake pedal and the steering levers) sendPWM signals to the Power Train ECM. The Power Train ECM then sends maximum current toall four of the (proportional) clutch and brake solenoids.

This maximum current completely ENERGIZES the solenoids, which close the poppets in thesolenoid valves and shuts off the flow of pump supply oil and pilot oil to drain. The result isincreased pilot pressure to all four pressure reducing spools. This increased pressure moves thereducing spools to the right.


Pressure ReducingSpool

Left ClutchSolenoid

Left BrakeSolenoid

Right BrakeSolenoid

Right ClutchSolenoid

To Right Brake

Supply Oil

To Left Brake

To Right Clutch

To Left Clutch

ParkingBrake

Solenoid

SecondaryBrake

Solenoid

ELECTRONICSTEERING AND BRAKE

CONTROL VALVESTRAIGHT TRAVEL

As the spools move to the right, the passages to the drain are closed off and the passages to thebrake and clutch circuits are opened. High pressure pump supply oil flows into the clutch andbrake passages and then out to the clutches and the brakes. This increased pressure ENGAGESthe clutches and DISENGAGES, or releases the brakes against their springs.

With the clutches ENGAGED and the brakes DISENGAGED, power is transferred to the leftand to the right final drives and the tracks move the machine in a straight line.


96

Illustration 96 shows the electronic steering and brake control valve when the brakes are fullyengaged.

When the operator depresses the service brake pedal, the brake pedal position sensor sends asignal to the Power Train ECM. The Power Train ECM then decreases the current to both theleft and the right proportional brake solenoids. The amount of current sent to the solenoid isdirectly proportional to the position of the service brake pedal.

The decreased current DE-ENERGIZES the solenoids, which open the poppets in the solenoidvalves and opens the flow of pump supply oil and pilot oil to drain. The result is decreased pilotpressure to both brake pressure reducing spools. This decreased pressure allows the springs tomove the brake reducing spools to the left.

As the spools move to the left, the passages from the brake circuits are connected to the drainpassages and the high pressure supply passages are closed off. This decreases the oil pressure toboth the left and the right brakes. The decreased pressure allows the brake springs to beginengaging the brakes.


To Right Brake

Supply Oil

To Left Brake

To Right Clutch

To Left Clutch

ParkingBrake

Solenoid

SecondaryBrake

Solenoid

ELECTRONICSTEERING AND BRAKE

CONTROL VALVESERVICE BRAKES ENGAGED

Pressure ReducingSpool

Left ClutchSolenoid

Left BrakeSolenoid

Right BrakeSolenoid

Right ClutchSolenoid

When the operator completely depresses the service brake pedal, the secondary brake switch isactivated. The secondary brake switch then connects the battery to the secondary brake solenoidand it is ENERGIZED. The secondary brake solenoid valve completely drains the brake pilotoil to tank, which causes the reducing spools to move all the way to the left. As the spools moveto the left, pump supply is completely closed off and the brake circuits are completely open tothe drain passages. This decreases the pressure to the brakes and the brakes are then fullyengaged. The clutches are still pressurized and ENGAGED however, and will try to move themachine against the brakes.


97

Illustration 97 shows the electronic steering and brake control valve with the parking brakesENGAGED. When the operator sets the parking brake switch to ON, the parking brake valvesolenoid is connected to the battery and the solenoid is ENERGIZED. The secondary brakesolenoid is also ENERGIZED by the Power Train ECM as a backup measure.

The left and the right proportional brake solenoids are also DE-ENERGIZED by the PowerTrain ECM when the parking brake switch is set to ON.

The parking brake valve and the secondary brake valve completely drain the pilot oil from theleft and right brake reducing spools to tank through the check valves. This causes the pilotpressure in the brake circuits to decrease and the brake reducing spools move to the left. As thespools move to the left, the high pressure supply passages are closed off and the passages fromthe brake circuits are connected to the drain passages, which decreases the pressure to thebrakes. This decreased pressure allows the brake springs to fully ENGAGE the brakes.

At the same time, both of the proportional steering clutch solenoids remain ENERGIZED. Withthe steering clutch solenoids ENERGIZED, high pressure supply to the steering clutches ismaintained. This high pressure supply keeps the steering clutches ENGAGED against thesprings.


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98

Illustration 98 shows the electronic steering and brake control valve with the right steeringclutch DISENGAGED.

When the operator pulls the right FTC steering control lever rearward, the right steering leverposition sensor sends a signal to the Power Train ECM. The Power Train ECM then decreasesthe current to the right proportional clutch solenoid. The amount of current sent to the solenoidis directly proportional to the position of the right FTC steering control lever.

The decreased current begins to DE-ENERGIZE the right clutch solenoid, which opens thepoppet in the solenoid valve and opens the flow of pump supply oil and pilot oil to drain. Theresult is decreased pilot pressure to the right steering clutch pressure reducing spool. Thisdecreased pressure allows the spring to move the reducing spool to the left.

As the spool moves to the left, the high pressure supply passage to the clutch is closed off andthe passage to the drain is opened. This spool movement begins decreasing the pressure in theright steering clutch circuit. The decreased pressure in the right steering clutch circuit allowsthe springs to begin DISENGAGING the right steering clutch.


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When the operator moves the right FTC steering control lever to approximately half of its traveldistance, the right proportional clutch solenoid is completely DE-ENERGIZED. The pilot oil tothe right steering clutch reducing spool is completely drained to tank, which allows the spring tomove the spool all the way to the left. This spool movement completely closes off pump supplyto the clutch circuit and completely opens the right clutch circuit to drain.

With no oil pressure to the clutch, the clutch springs completely DISENGAGE the right clutch.With the right clutch DISENGAGED, power is disconnected to the right track and the machinemakes a gradual right turn.


99

Illustration 99 shows the electronic steering and brake control valve with the right steeringclutch DISENGAGED and the right brake ENGAGED.

When the operator pulls the right FTC steering control lever rearward, past the half-wayposition, the right steering lever position sensor sends an increased signal to the Power TrainECM. The Power Train ECM then decreases the current to the right proportional brakesolenoid. The amount of current sent to the right brake solenoid is directly proportional to theposition of the right FTC steering control lever.

The decreased current DE-ENERGIZES the right brake solenoid, which opens the poppet in thesolenoid valve and opens the flow of pump supply oil and pilot oil to drain. The result isdecreased pilot pressure to the right brake pressure reducing spool. This decreased pressureallows the spring to move the reducing spool to the left. As the spool moves to the left, the highpressure pump supply passage to the brake is closed off and the passage from the right brakecircuit is opened to drain. This spool movement begins decreasing the pressure to the rightbrake. The decreased pressure allows the springs to begin ENGAGING the right brake.


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When the operator moves the right FTC steering control lever all the way to the rear, the rightproportional brake solenoid is completely DE-ENERGIZED. The pilot oil to the right brakereducing spool is completely drained to tank, which allows the spring to move the reducingspool all the way to the left.

This spool movement completely closes off pump supply to the brake circuit and completelyopens the right brake circuit to drain. With no oil pressure to the brake, the springs completelyENGAGE the right brake. With the right brake ENGAGED, the right track is completelystopped and the machine makes a sharp right turn.


The power train oil fill tube (1) and the power train oil dipstick (2) may be easily accessed byopening the spring-hinged door beside the step at the front of the left fender.

The remote mounted power train breather (3) is located inside the compartment at the rear of theleft fender. The breather is connected to the vent line that connects the torque divider case to themain case. The breather should be periodically cleaned. Refer to the Operation andMaintenance Manual for the D10T (Form No. SEBU7764) for the power train breathermaintenance intervals.

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Brake pressure for the left brake (B1) may be tested by removing the plug (1) at the top of theleft final drive and installing a pressure test tap. Clutch pressure for the left steering clutch (C1)may be tested in a like manner at the middle port (2). Lube pressure (LB1) for the left steeringclutch and left brake may also be tested at the rear port (3). The test ports for right brakepressure (B2) and for right steering clutch pressure (C2) are reversed on the right final drive.

The service brake pedal (4) is connected to a rotary position sensor (5). The rotary positionsensor sends a PWM signal to the Power Train ECM which, in turn, controls the proportionalsolenoids for the service brakes. The secondary brake switch may be accessed through thecover (6).

The status of service brake pedal position sensor and the secondary brake switch may be viewedthrough the Advisor panel (Service/System Status/Power Train screens) or by using Cat ET.

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The high speed oil change connector for power train oil (1) may be accessed by opening the leftengine compartment door and then unlatching and lowering the valance below the door opening.

If the machine is equipped with a single-shank ripper, the pin puller valve (2) and solenoid (3)are mounted to a bracket located at the right side of the transmission cover, near the top of thecover. The pin puller is activated with the pin puller rocker switch, which is located on the rightconsole in the operator's compartment. When the pin puller switch is moved to the "Pin Out"position, the solenoid is ENERGIZED. The valve uses power train oil to operate the hydraulicpin puller cylinder (not shown).

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IMPLEMENT HYDRAULIC SYSTEM

The implement hydraulic system has also been upgraded for the D10T. These upgrades include:

- a three-section, fixed displacement gear-type implement pump with approximately 7%more flow rate than the D10R;

- a new A4 Implement ECM;- the addition of a separate pressure reducing manifold and improvements to the electro-

hydraulic pilot manifold;- new proportional solenoid controlled pilot valves for all of the blade functions and

ON/OFF solenoid controlled pilot valves for all of the the ripper functions;- two 6-micron high efficiency hydraulic oil filters;- a remote mounted spin-on type pilot oil filter;- a larger hydraulic oil tank with approximately 35% more capacity than the D10R tank;- a hydraulic oil cooler that has been relocated to beneath the radiator; and- AutoCarry is now available as an attachment.


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The status of all of the sensors and solenoids in the implement hydraulic system may be viewedthrough the Advisor panel (Service/System Status/Implement screens) or by using Cat ET.

The D10T is equipped with an electro-hydraulic (EH) implement system similar to theimplement system used in the D10R. The Implement ECM receives input signals from theblade control lever position sensors, the ripper control lever position sensors, and various othersensors and switches. The ECM sends corresponding output signals to energize the appropriatesolenoid controlled pilot valves on the EH pilot manifold. The solenoid controlled pilot valvescontrol the amount of pilot oil that is sent to the dozer or the ripper control valves to shift theappropriate spools and direct implement pump oil to the head ends or rod ends of the implementcylinders.

The Implement ECM also sends corresponding output signals to energize the pitch and singletilt ON/OFF solenoid valve on the dual tilt valve. The pitch and single tilt ON/OFF solenoidvalve directs oil to shift the dual tilt valve, which determines blade tilt modes and pitch angles.

The implement hydraulic system for the D10T Track-type Tractor is a fixed displacement flowdesign that permits a minimum pressure in the system when the implement control valves arenot activated. The oil flow for operation of the bulldozer and the ripper is provided by twosections (lift and tilt) of the three-section implement gear pump.

The third (rear, or small) section of the implement pump supplies oil to the RATAAC fan motorand provides pilot oil for operation of the dual tilt valve, if the machine is equipped with dualtilt. The rear section of the implement pump also provides oil to the pressure reducing manifold,which supplies pilot oil to the EH pilot manifold for operation of the implement control valves.

A Pressure Compensation Override (PCO) valve provides engine overspeed protection when itis energized by the Engine ECM. The PCO valve is also energized by the Implement ECMwhenever a ripper function is requested. The PCO valve allows the dozer lift relief valve to actas the relief valve for the ripper circuit.

The resolver network transmits the highest implement cylinder pressure back to the pressurereducing manifold. The highest resolved pressure is directed through the pressure reducingmanifold by the diverter valve and acts as pilot oil for lowering the implements in the event thatthe engine will not run or the implement pump fails.

If the engine will not run and machine electrical power is not available, the "dead electric lower"(or manual lower) valve is used to lower the implements. The dead electric lower valve allowsthe flow of oil from the implement cylinders through the resolver network, and then to the thehydraulic oil tank. This allows the serviceman to slowly lower the implements.


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Implement Hydraulic System Component Identification

Most of the major components of the implement hydraulic system can be seen in the illustrationabove. The implement pump is not visible, above, but is mounted to the upper right, rear of theflywheel housing.

The dozer control valve (1) is mounted to the inside of the left fender. The dozer control valvecontrols the blade raise/lower/float functions and the blade tilt left/right functions.

The pressure reducing manifold (2) is mounted to the front of the main case. The pressurereducing manifold is supplied oil from the rear section of the gear-type implement pump (notvisible above), and in turn, supplies pilot oil to the EH pilot manifold via the pilot oil filter.

The EH pilot manifold (3) is mounted to the top of the main case and contains all the solenoidcontrolled pilot valves. The pilot valves supply pilot oil to the implement control valves for theoperation of all of the implement functions.

The ripper valve (4) is mounted to a bracket at the top rear of the main case. The ripper valvecontrols the ripper raise/lower functions and the ripper shank in/out functions.

The hydraulic tank is mounted to the rear of the right fender.


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The hydraulic tank is located on top of the right fender, forward of the right rollover supportpost. The hydraulic tank provides oil for the operation of the implements, the RATAAC fan, andthe hydraulic demand fan. Components and service points shown in the above illustration are:

1. the vacuum breaker2. the hydraulic filter access covers (two, 6-micron filters)3. the hydraulic oil fill tube and locking cap4. the hydraulic oil level sight glass5. the hydraulic oil sampling port (S•O•S)6. the hydraulic tank drain valve7. the hydraulic oil filter bypass switch (for the RATAAC and demand fan circuit filter)8. the RATAAC and demand fan circuit return9. the case drain return (to internal screen)

10. the hydraulic oil temperature sensor11. the main hydraulic oil suction manifold (for all hydraulic pumps)12. the implement circuit return


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The hydraulic oil tank contains two internal filters - one for return oil from the implements andone for the return oil from the demand fan and the RATAAC fan circuits. The hydraulic oil tankalso contains a screen for case drain return oil. (Not visible above, is the pilot oil drain return.It is located at the lower right. It is hidden in this illustration by the main suction manifold.)

The hydraulic filter bypass switch is a normally open pressure switch that senses the pressure ofthe return oil in the circuit (before the filter). The switch provides a signal to the ImplementECM at a specified pressure, indicating a filter restriction. Advisor will illuminate the ActionLamp and light, and display a warning on the Advisor panel that the hydraulic oil filter isclogged and is being bypassed.

The hydraulic oil temperature sensor (10) provides a signal to the Implement ECM. This signalis considered when using the Advisor panel or Cat ET to perform calibration routines of theimplement pilot valve solenoids. If the signal indicates the temperature of the oil is below thetemperature specified in the calibration routine conditions, the routine will be aborted.

The status of the hydraulic oil temperature sensor and the hydraulic oil filter bypass switch maybe viewed through the Advisor panel (Service/System Status/Implement screens) or by usingCat ET. Advisor also displays a digital readout of the hydraulic oil temperature on thePerformance 1 screen.

NOTE: The vacuum breaker on the hydraulic oil tank should always be used to equalize thepressure inside the hydraulic oil tank with the atmospheric pressure before removing the capfrom the filler tube. This will prevent scalding injuries due to hot hydraulic oil being expelledthrough the filler tube when the cap is removed.


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The three-section fixed displacement gear-type implement pump is mounted to the rear of theflywheel housing, at the upper right. This pump supplies oil to the implement valves, theRATAAC fan system, and the pressure reducing manifold.

The lift (front) section (1) supplies oil to the blade lift section of the dozer control valve and to theripper control valve. Pump discharge from the lift section is through the forward pump outlet (9).Discharge pressure for the lift section (HPD1) may be tested at the forward pressure test port (10),and may be monitored through the Advisor panel or by using Cat ET.

The tilt (middle) section (2) supplies oil to the blade tilt section of the dozer control valve. Pumpdischarge from the tilt section is through the middle pump outlet (7). Discharge pressure for thetilt section (HPD2) may be tested at the middle pressure test port (8), and may also be monitoredthrough the Advisor panel or by using Cat ET.

The rear section of the implement pump (3) supplies oil to the RATAAC fan motor through thepilot pressure and RATAAC fan speed control valve (6). The rear section also provides oil to thepressure reducing manifold. This oil is pilot oil for the EH pilot manifold and for the dual tiltvalve. The two discharge pressure test ports on the RATAAC fan speed control valve are used totest Hydraulic Fan Pump Discharge pressure (HFPD) (4) and Hydraulic Fan Motor Inlet pressure(HFMI) (5). The Hydraulic Fan Motor Inlet Pressure is the RATAAC fan system pressure.


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INSTRUCTOR NOTE: The following standby pressures may be observed during labexercises.

- Lift pump (HPD1) pressure at high idle (implements in HOLD) should be approximately760 kPa (110 psi).

- Tilt pump (HPD2) pressure at high idle (implements in HOLD) should be approximately827 kPa (120 psi).

- Small pump (HFPD) pressure at high idle (implements in HOLD) should be approximately5860 kPa (850 psi).

Always refer to the latest revision of the Service Manual for your machine serial number,"Specifications, Systems Operation, Testing and Adjusting - Hydraulic System" (FormNo. RENR7540) for the most recent specifications of system pressures.


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Shown above is the dozer control valve. It is mounted to the inside of the right fender, abovethe right frame rail. It may be accessed by removing the floor plates in the operator'scompartment. The dozer control valve is supplied with oil from the lift and tilt sections of theimplement pump. The oil from both sections of the pump is combined when raising or loweringthe blade. When tilting the blade left or right, the oil from the two sections is segregated so thatonly the oil from the tilt section of the implement pump is used for tilting the blade and the oilfrom the lift section of the implement pump is used for raising and lowering the blade.

High pressure pump supply oil from the lift (front) section of the implement pump enters thedozer valve at the dozer lift valve inlet (4). High pressure pump supply oil from the tilt (middle)section of the implement pump enters the dozer valve at the dozer tilt valve inlet (8).

The lift pump pressure sensor (3) is installed at the dozer lift valve inlet. This sensor detects theHydraulic Pump Discharge pressure (HPD1) in the lift circuit. The status of this sensor may beviewed using the Advisor panel (Service/System Status/Implement screens) and is identified as"Main Hyd Pump Oil Pressure." The tilt pump pressure sensor (5) is installed at the dozer tiltvalve inlet. This sensor detects the Hydraulic Pump Discharge pressure (HPD2) in the tiltcircuit. The status of this sensor may also be viewed using the Advisor panel (Service/SystemStatus/Implement screens) and is identified as "Tilt Hyd Pump Oil Pressure."


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High pressure pump supply oil is sent to and returns from the dozer lift cylinders through thelarger high pressure hydraulic lines (2). High pressure pump supply oil is sent to and returnsfrom the dozer tilt cylinder (or the dual tilt valve) through the smaller high pressure hydrauliclines (1).

High pressure pump supply oil to the ripper valve is sent through a hose connected to the rippersupply outlet (9). This oil is a combination of the flows from both the lift and the tilt sections ofthe implement pump, unless a blade tilt function is commanded. During blade tilt operation,only the lift section of the implement pump supplies oil to the ripper valve.

Return oil from the ripper cylinders flows into the implement return oil manifold (6) through themanifold inlet (7) where it combines with the return oil from the lift cylinders and the tiltcylinders. The combined return oil is then directed back to the hydraulic tank where it is filteredbefore being recirculated by the implement pump.

The signals from the two implement pump pressure sensors are considered by the ImplementECM for the operation of several implement system strategies. The following list outlines whenthe sensors are used:

- During the solenoid calibration routines for the implement pilot valves (using Advisor orCat ET), the Implement ECM looks for a drop in implement pump discharge pressure todetermine the amount of solenoid current needed to move an implement. When the pilotpressure becomes great enough to move the implement control valve spool, high pressuresupply oil begins to flow past the main valve spool and out to the implement cylinders.This will cause a brief drop in pressure in that circuit. The drop in pressure causes achange in signal from the sensor that indicates the necessary current value has beenachieved and the Implement ECM will store this value in its memory.

- The signal from the lift pump sensor is also used for the ripper AutoStow strategy. Whenthe operator presses the AutoStow switch, the Implement ECM energizes the ripper raisesolenoid and the PCO valve solenoid (and either the ripper tip in or ripper tip out solenoid,if AutoStow is so configured). The ripper will then raise until the end of the cylinderstroke is reached. When the end of cylinder stroke is attained, the hydraulic systempressure rises and the sensor signal reflects the change in pressure. This change in signalindicates that the end of stroke has been attained and the Implement ECM will then de-energize the implement solenoids.

- During the operation of the ABA or the AutoCarry cycles, the Implement ECM looks for achange in the signal from either sensor. The change in signals indicate when the tiltcylinders have reached the end of stroke during the "spread" and "blade reset" segments ofthe automatic cycles, and when the lift cylinders have reached the end of stroke during the"raise" and "return" segments of the automatic cycles.


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The ripper control valve assembly is shown in the illustration above. It is mounted to the rear ofthe main case, above the transmission inspection cover and below the fuel tank. The rippercontrol valve controls the ripper raise/lower functions and the shank in/out functions.

The ripper valve contains two valve sections - the ripper shank in/out valve section (3) and theripper raise/lower valve section (4).

The ripper valve is supplied with high pressure oil from the lift section of the implement pumpand from the tilt section, when the blade tilt function is not activated. Pump supply oil to theripper valve flows through the far high pressure hydraulic hose (1). Return oil from the rippercylinders flows through the near high pressure hydraulic hose (2) to the return oil manifold, andthen back to the hydraulic oil tank.

High pressure supply oil to the right ripper shank cylinder and return oil from the right rippershank cylinder is through the rear hose connections (5). High pressure supply oil to the rightripper raise cylinder and return oil from the right ripper raise cylinder is through the forwardhose connections (6). Identical connections for the left ripper lift and shank cylinders arelocated in the same positions on the left side of the valve assembly.


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The hard steel line (7) connects the two internal supply passages to the ripper lift valve with anexternal resolver valve. The highest resolved pressure is transmitted through the resolvernetwork so that the ripper may be lowered manually with the dead electric lower valve. Ifelectricity is available, the ripper control control handle can be used to lower the ripper in a deadengine situation.

A ripper warming valve will be installed in the ripper control valve on machines equipped witha cold weather arrangement. The warming valve allows a small amount of warm hydraulic oilto circulate through the valve body and return to tank when the ripper is not being operated. Thewarming valve helps prevent thermal shock from occurring inside the valve when a ripperfunction is requested in an extremely cold environment. Without the ripper warming valve, hotoil could cause a cold valve stem to expand faster than the valve body, causing the valve stem toseize in the valve body during ripper operation.


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The hydraulic oil cooler (1) is an oil-to-water type cooler. It is located beneath the radiatorguard. Return oil from the hydraulic demand fan enters the cooler at the cooler inlet (2). Thecooler bypass valve is contained inside the housing (3). Only return oil from the hydraulicdemand fan passes through the hydraulic oil cooler.

The cooler bypass valve is pressure activated, only. The thicker (more viscous) oil creates morepressure, which causes the bypass valve to open when the oil is cold. This allows most of the oilto bypass the cooler. Once the oil is warm (less viscous), the pressure is less for the samevolume of oil and the bypass valve remains closed. All of the oil from the demand fan motorwill then pass through the cooler.

All of the oil exits the cooler, or the bypass valve, through the cooler outlet (4) and returns to thehydraulic oil tank in either condition.


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Pilot Hydraulic System

The pressure reducing manifold (1) is located on the front of the main case, below the EH pilotmanifold. The pressure reducing manifold contains the pressure reducing valve (10). Thepressure reducing valve lowers the pressure of implement pump supply oil from the pilotpressure and RATAAC fan speed control valve. The pump supply oil enters the manifold at theinlet (3). The Hydraulic Pilot Supply (HPS) pressure may be tested at the pressure test port (5),installed on the bottom of the pressure reducing manifold.

The line from the resolver network circuit (2) supplies oil to the diverter valve (11) when theengine is OFF and the implements are raised above the ground.

After the oil is reduced to pilot pressure it is directed to the pilot oil filter through a hoseconnected to the fitting at the manifold outlet (4).

The implement lockout valve is operated by the solenoid (6) that is installed in the left side ofthe pressure reducing manifold.

Oil that flows past the dead electric lower valve (9) or oil that flows past the pilot relief valve (8)is directed back to the hydraulic tank through the hard steel line (7).


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The pressure reducing manifold supplies pilot supply oil to the EH pilot manifold via the pilotoil filter, and to the AutoCarry diverter valve (if the machine is equipped with AutoCarry). Thepressure reducing manifold is supplied with oil from the rear section of the implement pump,through the pilot pressure and RATAAC fan speed control valve.

Oil enters the pressure reducing manifold and passes through a screen before it reaches thediverter valve. High pressure pump supply oil acts on the end of the diverter valve to move itup, against the spring. The supply oil passes through the diverter valve, where it enters thepressure reducing valve. The pressure reducing valve is infinitely variable, and meters the oil toprovide pilot oil pressure of approximately 4000 ± 207 kPa (580 ± 30 psi), at high idle.

The reduced pressure pilot oil then passes through the implement lockout valve. The implementlockout valve is solenoid controlled and is ENERGIZED in the UNLOCKED position. TheON/OFF solenoid is controlled by the implement lockout switch, which is located on the rightconsole in the operator's compartment. The implement lockout valve is DE-ENERGIZED in theLOCKED position and the supply of pilot oil to the EH pilot manifold is blocked. Theimplements cannot be moved using the implement controls when the implement lockout valvesolenoid is DE-ENERGIZED and the valve is in the LOCKED position.


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When engine speed is below 900 rpm, the Implement ECM automatically DE-ENERGIZES theimplement lockout solenoid and the valve is in the LOCKED position. The solenoid will beENERGIZED as soon as an implement control is moved. This strategy helps prevent inadvertentimplement movement during service procedures by shutting off the pilot supply to the EHmanifold.

When the operator activates an implement, the appropriate solenoid controlled pilot valve directsthe pilot oil into the pilot chamber of the implement control valve. The pilot pressure then shiftsthe implement valve spool. From the implement lockout valve, the pilot oil is directed to theremote mounted pilot oil filter. The oil is directed to the EH pilot manifold from the pilot oil filter.

Also contained in the pressure reducing manifold is the pilot relief valve. The pilot relief valvelimits the pressure past the pressure reducing valve to approximately 6500 kPa (940 psi). Thisvalve opens to dissipate the excess pressure, in the event of pressure spikes in the pilot system.When the implement lockout valve is in the LOCKED condition, the pilot relief valve opens todirect the flow of pilot oil back to the hydraulic oil tank.

The diverter valve is used to provide pilot pressure for lowering the implements in a dead enginesituation. When the engine is OFF and any implements are suspended above the ground, theweight of the implements creates pressure in the rod ends of the ripper and/or blade lift cylinders.The highest resolved pressure from the implement cylinders is transmitted through the resolvernetwork and is directed into the passage between the diverter valve and the dead electric lowervalve. With no supply oil pressure from the implement pump, the spring in the pilot operateddiverter valve moves the valve down, allowing the highest resolved pressure from the resolvernetwork to pass through to the pressure reducing valve. This oil now becomes pilot oil forlowering the implements. The implements may be lowered using the EH implement controls in theoperator's compartment until all implements come into contact with the ground (if there is electricpower available to the implement controls) in this condition.

In a dead (no) electric situation, the EH implement controls will not function. The implementsmust be slowly lowered by manually adjusting out the dead electric lower valve (screw andlocknut). This will allow all the oil from the rod ends of the ripper lift cylinders and the dozer liftcylinders to slowly drain to the hydraulic tank through the resolver network until the implementscome into contact with the ground.

INSTRUCTOR NOTE: During lab exercises, the following pressures may be observed:

- The sequencer valve on the RATAAC fan speed control valve supplies oil to the pressurereducing manifold. The sequencer valve is is adjusted at low idle and the pressure observed(HFPD) should be approximately 4068 kPa (590 psi).

- Hydraulic Pilot Supply (HPS) should be tested at high idle, with the implement lockout switchset to ON. The pilot pressure (HPS) should be approximately 4000 kPa (580 psi).

Always refer to the latest revision of the Service Manual for your machine serial number,"Specifications, Systems Operation, Testing and Adjusting - Hydraulic System" (Form No.RENR7540) for the most recent specifications of system pressures.


115

The remote mounted pilot oil filter base is mounted to the inside of the right fender, toward thefront. It may be accessed by removing the cover beside the step at the front of the right fender.

The pilot oil filter (1) is a spin-on type filter.

Pilot oil from the pressure reducing manifold enters the filter base at the filter inlet (2). Thepilot oil returns to the EH pilot manifold through a line connected to the outlet of the filter base (3) after the oil is filtered.

The filter base contains a filter bypass valve, but no filter bypass switch.

Filtration of the pilot oil is very important to ensure the proper operation of the implementsystem. Contaminants in the pilot oil will clog the small openings in the solenoid controlledpilot valves and could cause damage to the valve's small components. Refer to the D10TOperation and Maintenance Manual (OMM) (Form No. SEBU7764) for recommendationsconcerning filter change frequency intervals.


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The EH pilot manifold (1) is located on top of the main case, below the floor plates in theoperator's compartment. Reduced pressure pilot oil is sent to the pilot oil filter from thepressure reducing manifold. The filtered pilot oil returns to the EH pilot manifold and enters themanifold at the inlet fitting (4). The pilot oil is then distributed to each of the solenoid valvesthrough internal passages in the manifold.

When an implement lever is moved, the Implement ECM energizes the appropriate solenoid (2),sending pilot oil to the implement control valve, which shifts the main valve spool. The pilotpressure to that implement control valve may be tested at the corresponding pressure test port (3) while the implement is moving.

Return oil from the pilot relief valve and the dead electric lower valve in the pressure reducingmanifold flows through the hard steel line (6) where it combines with return oil from the pilotmanifold at the "tee" fitting (5). This oil then returns to the hydraulic oil tank.


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The EH pilot manifold receives pilot supply oil from the pressure reducing manifold, after passingthrough the pilot oil filter. The EH pilot manifold contains four proportional solenoid valves thatreceive PWM signals from the Implement ECM for operating the blade lift and the blade tiltfunctions. The EH pilot manifold also contains five ON/OFF solenoid valves - two each for theripper raise/lower function and the ripper shank in/out function, and one solenoid valve for engineoverspeed protection and ripper operation (PCO valve). All of these solenoid valves are presentas standard equipment, regardless of attachments. Each solenoid valve has a correspondingpressure tap for checking the pilot pressure to the implement control valve (except the PCO valve,which has a plug installed instead of a pressure tap).These nine solenoid valves are:

- blade raise, or dozer raise solenoid (DR)- PCO valve solenoid (RV)- blade tilt left solenoid (TL)- blade tilt right solenoid (TR)- blade lower/float, or dozer lower solenoid (DL)- ripper shank out, or tip out solenoid (TO)- ripper lower, or ripper down solenoid (RD)- ripper shank in, or tip in solenoid (TI)- ripper raise, or ripper up solenoid (RU)


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For blade lift and blade tilt control, the solenoid plunger movement is proportional to theelectrical current sent from the Implement ECM. Solenoid plunger position determines theamount of pilot oil pressure felt at the ends of the dozer lift and tilt spools. An increase inelectrical current causes an increase in oil pressure which moves the dozer lift and the dozer tiltcontrol valve spools proportionately. The electrical current sent to the dozer lift and tilt solenoidsby the Implement ECM is in direct proportion to the amount of movement of the dozer controllever by the operator.

The Implement ECM sends only high current signals to the PCO valve solenoid and the rippersolenoid valves. These five solenoid valves are ON/OFF solenoid valves. They operate similarlyto the dozer lift and dozer tilt solenoid controlled pilot valves. However, the five ON/OFFsolenoid controlled pilot valves provide full pilot oil pressure to the ends of the ripper lift andripper tip control valve spools when they are energized.

(Refer to the D10T hydraulic system schematic for the rest of the explanation that follows.)

The Pressure Control Override (PCO) valve provides engine overspeed protection when it isenergized by the Engine ECM. Energizing the PCO valve solenoid directs pilot oil to the end ofthe shuttle valve (contained in the dozer control valve). The shuttle valve then directs highpressure implement pump supply oil to the end of the dump valve, shutting off the flow of highpressure pump oil to tank. This condition causes an extra load on the fixed displacementimplement pump, which increases the load on the engine and slows engine rpm.

The PCO valve is also energized whenever a ripper function is requested. When the operatorrequests a ripper function, the PCO valve is energized by the Implement ECM. The PCO valveagain directs pilot oil to shift the shuttle valve (in the dozer control valve), shutting off the flow ofhigh pressure pump oil to tank. This ensures that maximum oil pressure is available for ripperoperation. In either of these situations, the PCO valve causes the dozer lift relief valve to act asthe relief valve for the ripper circuit and for the engine overspeed situation.

INSTRUCTOR NOTE: The following pilot pressures should be observed at the pilotpressure test ports on the EH pilot manifold during lab exercises.

- Dozer RAISE (HPDR) pressure should be approximately 3100 kPa (450 psi).- Dozer LOWER (HPDL) pressure should be approximately 1725 kPa (250 psi).- Dozer FLOAT (HPDL) pressure should be approximately 3450 kPa (500 psi).- TILT LEFT/RIGHT (HPTL/HPTR) - pressures should be approximately 3100 kPa (450 psi).- ALL ripper functions - pressures should be approximately 3100 kPa (450 psi).- Hydraulic Pilot Supply (HPS) at the pressure reducing manifold should be approximately

4000 kPa (580 psi).Always refer to the latest revision of the Service Manual for your machine serial number,"Specifications, Systems Operation, Testing and Adjusting - Hydraulic System" (Form No.RENR7540) for the most recent specifications of system pressures.


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Dozer Control Valve

The dozer control valve contains a four position blade lift spool (RAISE, HOLD, LOWER, andFLOAT) and a three position blade tilt spool (TILT RIGHT, HOLD, and TILT LEFT). Theblade lift spool is a "closed-center" spool, and the blade tilt spool is an "open-center" spool. Inthis view and that on the next page, the dozer valve is shown in the BLADE RAISE condition.Refer to illustration No. 118 and No. 119 during the explanation of the BLADE RAISE functionthat accompanies the illustration of the hydraulic schematic, later in this presentation. The dozervalve contains the following major components:

Blade Lift Spool: A closed-center valve that controls the flow of oil to the blade lift cylinders.When in the RAISE or LOWER position, the lift spool also sends oil to the signal resolver,which in turn sends the oil through the shuttle valve to a passage between the lift relief valveand the lift dump valve.

Blade Tilt Spool: An open-center valve that controls the flow of oil from the tilt section of thehydraulic oil pump to the blade tilt cylinder(s) when the spool is moved for a tilt function. Inthe normal center position, oil from the tilt section of the implement pump flows past the spooland combines with the oil from the lift section. When in the TILT RIGHT or TILT left position,oil is also sent to a passage between the tilt dump valve and the tilt relief valve.


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119

Signal Resolver: During blade lift functions, the cylinder load pressure signal is transmitted tothe signal resolver valve, through the shuttle valve, to the spring chamber of the dump valve.The cylinder load pressure signal is from the lift cylinder rod end during RAISE and from thecylinder head end during LOWER. The signal resolver valve directs the higher of the cylinderrod or head end pressure to the shuttle valve.

Shuttle Valve: In its normally spring biased position, the shuttle valve directs pump supply oilto a passage between the blade lift relief valve and the blade dump valve during blade liftfunctions. In an engine overspeed condition or during a ripper function, the PCO valve isenergized. This sends pilot oil to shift the shuttle valve, which opens a passage for oil to bemade available to the blade lift relief valve and blade lift dump valve available to the systemduring these two conditions.

Lift Relief Valve: During blade lift functions, lift cylinder load pressure is sent through thesignal resolver valve and the shuttle valve to a passage between the blade lift relief valve and theblade lift dump valve. The relief valve for the blade lift circuit limits the maximum pressure inthe blade lift circuit. The blade lift relief valve is set to approximately 18790 kPa (2725 psi).


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Lift Dump Valve: During blade lift functions, lift cylinder load pressure is sent through thesignal resolver valve and the shuttle valve to a passage between the blade lift relief valve and theblade lift dump valve. The cylinder pressure keeps the dump valve closed, which shuts off theflow of pump supply oil to tank. This ensures that maximum system pressure is available for liftcylinder operation. The lift dump valve should maintain a minimum lift circuit pressure ofapproximately 400 kPa (58 psi) at low idle, and approximately 760 kPa (110 psi) at high idle.

Tilt Relief Valve: During blade tilt functions, tilt cylinder load pressure is sent to a passagebetween the tilt relief valve and the tilt dump valve. The relief valve for the blade tilt circuitlimits the maximum pressure in the blade tilt circuit. The tilt relief valve is set to approximately20,340 kPa (2950 psi).

Tilt Dump Valve: During blade tilt functions, tilt cylinder load pressure is sent to a passagebetween the tilt relief valve and the tilt dump valve. The tilt cylinder pressure keeps the dumpvalve closed, which shuts off the flow of pump supply oil to tank. This ensures that maximumtilt circuit pressure is available for tilt cylinder operation. The tilt dump valve should maintain aminimum tilt circuit pressure of approximately 415 kPa (60 psi) at low idle, and approximately830 kPa (120 psi) at high idle.

Load Check Valve: The load check valve prevents reverse oil flow from the implementcylinders when the main valve spool moves from the HOLD position and system pressure islower than the cylinder, or work port pressure. Without the load check valve, the implementwould drift down slightly (droop) before moving as commanded. The load check valve willopen to allow supply oil to flow through the control valve when the system pressure is higherthan the work port pressure.

Makeup Valve: The makeup valves are only present on the blade lift circuit in the dozer valve.There is one makeup valve for the rod-ends and one for head-ends of the blade lift cylinders.These valves are held closed by a spring. The makeup valves open whenever workport pressurefalls below tank pressure. In a quick-drop situation, the makeup valve for the head-ends of thelift cylinders will open to allow tank oil to supplement pump flow. When in FLOAT, themakeup valve for the rod-ends of the lift cylinders may open if the blade rises quickly. (Themake-up valve for the head-ends of the lift cylinders will not open, however, when the bladedrops during the FLOAT condition. This is due to a slight head-end pressure in the liftcylinders, which will be discussed later in this presentation.)


120

Dozer Lift and Tilt Circuits

Shown above is a color schematic of the D10T implement hydraulic system in the BLADERAISE condition. Refer to illustrations No. 118 and No. 119 to see the state of the dozer controlvalve components during the following explanation of the dozer lift circuit.

When the operator moves the dozer control lever from HOLD to RAISE, a signal is sent to theImplement ECM. The Implement ECM in turn sends a signal to energize the solenoid of theBLADE RAISE pilot valve on the EH pilot manifold (HPDR). The BLADE RAISE pilot valvethen directs pilot oil to shift the blade lift spool to the right, into RAISE position.

The combined high pressure oil from the lift section and the tilt section of the implement pumpthen flows past the internal load check valve and the blade lift spool, then out to the rod ends ofthe lift cylinders to raise the blade. As the blade is raised, oil from the head end of the liftcylinders returns through the head end passage of the dozer control valve and flows past theblade lift spool, and then into the passage to the hydraulic tank.

INSTRUCTOR NOTE: Refer back to the color cutaway illustrations of the dozer valve(illustrations No. 118 and No. 119) during the next few paragraphs of the explanation.


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At the same time, high pressure oil from the cylinder rod end passage flows through machinedslots in the leftmost land of the main valve spool and into the signal resolver passage. This oilshifts the signal resolver ball to the right and the oil enters the passage to the shuttle valve. Thehigh pressure oil then flows around the center stem of the shuttle valve and enters a passage thatdirects the oil to the spring chamber between the lift relief valve and the dump valve.

The high pressure oil in the spring chamber plus the force of the spring keeps the dump valve inthe closed position so that maximum oil pressure is available to move the lift cylinders.

INSTRUCTOR NOTE: Refer back to the color schematic (illustration No. 120) for theremainder of the explanation.

At the same time that high pressure oil flows out to the rod ends of the lift cylinders, highpressure oil also flows into the resolver connected to the rod end passage of the to the liftcylinders. If this is the highest pressure in the implement system, this pressure is transmittedthrough the rest of the resolvers in the resolver network, then on to the diverter valve, containedin the pressure reducing manifold, where it is blocked at the diverter valve.

If the engine is OFF and the blade is suspended, gravity causes the weight of the blade toproduce high pressure oil in the rod ends of the lift cylinders. With no pressure present from thepilot oil section of the pump, the diverter valve is forced down by its spring, which then directsthe highest resolved pressure from the resolver network to the pressure reducing valve. Thiswill now serve as pilot oil pressure for lowering the implements with the implement controls.

If electricity is not available for lowering implements with the implement controls or if theimplement controls have failed, the implements can be lowered manually by opening the "DeadElectric Lower Valve", also contained in the pressure reducing valve. This procedure slowlydrains the oil from the rod ends of the lift cylinders through the resolver network and back to thetank.


121

Shown above is a color schematic of the D10T implement hydraulic system in the BLADEFLOAT condition. Refer to illustration No. 122 to see the state of the dozer control valvecomponents during the following explanation of the dozer lift circuit.

When the operator moves the dozer control lever from HOLD to FLOAT, a signal is sent to theImplement ECM. The Implement ECM in turn sends a signal to energize the solenoid of theBLADE LOWER/FLOAT pilot valve on the EH pilot manifold (HPDL). The BLADELOWER/FLOAT pilot valve then directs pilot oil to shift the blade lift spool to the left, into theFLOAT position.

INSTRUCTOR NOTE: Refer to the color cutaway illustration of the dozer lift valve (illustration No. 122) during the next few paragraphs of the explanation.

The combined high pressure oil from the lift section and the tilt section of the implement pumpflows past the internal load check valve to the blade lift spool. When the blade lift spool isshifted all the way to the left, the rod ends of the lift cylinders are open to tank. However, thehead ends of the lift cylinders are only partially open to the tank passage. The head ends of thelift cylinders are partially open to the pump supply passage, also. This results in a slightpressure in the head-end of both lift cylinders. Although the blade will follow the contour of theground in FLOAT, there is a slight resistance to the blade rising and the blade is quick to fall.


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122

Because the head ends of the lift cylinders have a slight pressure present, the signal passagefrom the head ends of the lift cylinders to the signal resolver are at the same pressure. Thisslight pressure shifts the resolver ball to the left, allowing this low pressure to be felt at the endsof the lift relief valve and the lift dump valve.

INSTRUCTOR NOTE: Refer back to the color schematic (illustration No. 121) for theremainder of the explanation.

Although there is a slight pressure in the chamber between the lift relief valve and the lift dumpvalve, the high pressure oil in the lift circuit keeps the dump valve in the open position so thatpump flow is returned to tank.

Also note that as the blade follows the contour of the ground in FLOAT, the makeup valve forthe head-ends of the lift cylinders will not open if the blade falls quickly over a short distance.This is due to the slight pressure in the head-ends of the lift cylinders, which is also felt againstthe makeup valve in that side of the circuit. As the blade falls, pump flow will fill the void,which also serves to prevent the makeup valve from opening.


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123

Shown above is a color schematic of the D10T implement hydraulic system in the BLADE TILTLEFT condition. Refer to illustration No. 124 to see the state of the tilt control valvecomponents during the following explanation of the dozer tilt circuit.

When the operator moves the dozer control lever from HOLD to TILT LEFT, a signal is sent tothe Implement ECM. The Implement ECM in turn sends a signal to energize the solenoid of theBLADE TILT LEFT pilot valve on the EH pilot manifold (HPTL). The BLADE TILT LEFTpilot valve then directs pilot oil to shift the blade tilt spool to the left, into the TILT LEFTposition.

INSTRUCTOR NOTE: Refer to the color cutaway illustration of the dozer tilt valve (illustration No. 124) during the next paragraph of the explanation.

The high pressure oil from the tilt section of the implement pump then flows past the leftinternal load check valve and the blade tilt spool, and then out through the tilt cylinder head endpassage of the dozer valve to the head end of the (right) tilt cylinder. The left side of the blade isbraced against the blade push-arm to provide the mechanical leverage to tilt the blade.


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124

INSTRUCTOR NOTE: Refer back to the color schematic (illustration No. 123) for therest of the explanation.

As the cylinder rod extends, it forces oil from the rod end of the tilt cylinder back to the tiltcylinder rod end passage of the dozer valve where it flows past the tilt valve spool, and into thehead end tank passage back to the hydraulic oil tank.

At the same time that high pressure oil flows out to the right tilt cylinder, high pressure oil alsoflows into the resolver connected to the tilt cylinder head end passage of the dozer valve. If thisis the highest pressure in the implement system, this pressure is transmitted to the diverter valve,contained in the pressure reducing manifold, where it is blocked at the diverter valve.

The TILT RIGHT function operates in the same fashion, except that the tilt spool is shifted tothe right and oil flows into the rod end of the tilt cylinder . Oil from the head end of the tiltcylinder flows back to the hydraulic oil tank.


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125

Shown above is a color schematic of the D10T implement hydraulic system in the BLADE TILTLEFT condition, with DUAL TILT. Refer to illustration No. 124 to see the state of the tiltcontrol valve components during the following explanation of the dozer tilt circuit.

When the operator moves the dozer control lever from HOLD to TILT LEFT, a signal is sent tothe Implement ECM. The Implement ECM in turn sends a signal to energize the solenoid of theBLADE TILT LEFT pilot valve on the EH pilot manifold (HPTL). The BLADE TILT LEFTpilot valve then directs pilot oil to shift the blade tilt spool to the left, into the TILT LEFTposition.


The high pressure oil from the tilt section of the implement pump then flows past the leftinternal load check valve and the blade tilt spool, and then out through the tilt cylinder head endpassage of the dozer valve to the dual tilt valve.



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From the dual tilt valve, the oil flows to the head end of the right tilt cylinder and the cylinderrod extends, which causes the right side of the blade to move up. As the right tilt cylinder rodextends, it forces oil from the rod end back to the dual tilt valve where the oil is then directed toflow to the rod end of the left tilt cylinder. The left tilt cylinder rod then retracts, which causesthe left side of the blade to move down.

As the left cylinder rod retracts, it forces oil from the head end of the left tilt cylinder back to thedual tilt valve. This oil then flows back to the tilt cylinder rod end passage of the dozer valvewhere it flows past the tilt valve spool, and into the head end tank passage back to the hydraulicoil tank.

At the same time that high pressure oil flows out to the right tilt cylinder, high pressure oil alsoflows into the resolver connected to the tilt cylinder head end passage. If this is the highestpressure in the implement system, this pressure is transmitted from the resolver network to thediverter valve, contained in the pressure reducing manifold, where it is blocked at the divertervalve.

The TILT RIGHT function operates in the same fashion, except that the oil flows into the headend of the left tilt cylinder, from the rod end of the left tilt cylinder to the rod end of the right tiltcylinder, and then from the head end of the right tilt cylinder back to the hydraulic oil tank.

NOTE: When a single tilt function is requested on a machine equipped with dual tilt,the RIGHT tilt cylinder is isolated by the dual tilt valve and acts as the brace for themechanical leverage needed to tilt the blade. This is the opposite strategy used on asingle tilt machine, which uses a single tilt cylinder on the right and a brace on the left.Dual tilt operation will be discussed in greater detail, later in this presentation.


126

Ripper Control Valve

The ripper control valve contains two "closed-center" spools. One spool controls ripper RAISEand LOWER. The other spool controls ripper SHANK IN and SHANK OUT. The dozer valvecontains the following major components:

Ripper Raise Spool: A closed-center valve that controls the flow of oil to and from the ripperlift cylinders. When in the RAISE or LOWER position, the ripper raise spool also sends oil toan external signal resolver, which in turn sends the oil through the series of resolvers in theresolver network and then to the diverter valve in the pressure reducing manifold.

Ripper Tip Spool: A closed-center valve that controls the flow of oil to and from the ripper tipcylinders. No oil is sent to the series of resolvers in the resolver network during a ripper tipfunction.

Load Check Valve: The load check valve prevents reverse oil flow from the implementcylinders when the main valve spool moves from the HOLD position and system pressure islower than the cylinder, or work port pressure. Without the load check valve, the implementwould drift slightly (droop) before moving as commanded. The load check valve will open toallow supply oil to flow through the control valve when the system pressure becomes higherthan the work port pressure.


Pump Inlet (Combined)

Pilot Supply(Ripper Lower)

Pilot Supply(Shank Out)

Pilot Supply(Shank In)

Pilot Supply(Ripper Raise)

Load CheckValve

Ripper Raise Spool

RipperTip Spool

Tank Passage

Passage to Rod EndPassage to Head End

Tank Passage

Passage toHead End

Passage toRod End

Plug orRipper Warming

Valve

D10T RIPPER CONTROL VALVERIPPER RAISE

Makeup Valve: There are two makeup valves present in the ripper control valve. The makeupvalves open whenever workport pressure falls below tank pressure. One makeup valve is in thehead end circuit for ripper raise and will open if the ripper falls faster than the pump's ability tosupply oil to the head end of the ripper lift cylinders. The other makeup valve is in the rod endof the circuit for the ripper tip and will open if the ripper shank (tip) is forced rearward whenusing the ripper. (The makeup valves are not shown in illustration No. 126.)

The ripper valve contains no relief valves or dump valves. During any ripper operation, thePCO pilot valve on the EH pilot manifold is energized. The PCO pilot valve sends pilot oil tothe end of the shuttle valve (contained in the dozer valve) to shift it. When the shuttle valveshifts, high pressure pump supply oil is directed by the shuttle valve to the passage between thelift dump valve and the lift relief valve. This strategy closes the lift dump valve to block theflow of combined pump supply oil to tank and also uses the lift relief valve as the relief valvefor the ripper circuit.


127

Ripper Lift and Tip Circuits

Shown above is a color schematic of the D10T implement hydraulic system in the RIPPERRAISE condition. Refer to illustration No. 126 to see the state of the ripper control valvecomponents during the following explanation of the ripper raise circuit.

When the operator moves the ripper lift control from HOLD to RAISE, a signal is sent to theImplement ECM. The Implement ECM in turn sends a signal to energize the solenoids for theRIPPER RAISE pilot valve and the PCO pilot valve on the EH pilot manifold (HPRR andHPRV). The RIPPER RAISE pilot valve then directs pilot oil to shift the ripper raise spool tothe right, into the RIPPER RAISE position. The PCO valve directs pilot oil to shift the shuttlevalve down, which directs high pressure pump supply oil into the passage between the lift dumpvalve and the lift relief valve (in the dozer valve). The high pressure oil in this passage plus theforce of the spring keeps the dump valve in the closed position so that maximum oil pressure isavailable to move the ripper cylinders. The lift relief valve is also available to be used as therelief valve for the ripper circuit.

INSTRUCTOR NOTE: Refer to the color cutaway illustration of the ripper controlvalve (illustration No. 126) during the next paragraph of the explanation.


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The high pressure oil from the implement pump then flows past the internal load check valveand the ripper raise spool, and then out through the rod end passages to the ripper lift cylinders.This causes the ripper cylinder rods to retract and the ripper raises.

As the ripper lift cylinder rods retract, head end oil from the ripper lift cylinders flows back tothe ripper control valve through the ripper raise head end passages in the control valve. Thisreturn oil flows past the ripper raise spool and into the tank passage and then returns to thehydraulic oil tank.


At the same time that high pressure oil flows out to the rod ends of the ripper lift cylinders, highpressure oil also flows into the resolver connected to the rod end passage to the ripper liftcylinders. If this is the highest pressure in the implement system, this pressure is transmittedthrough the rest of the resolvers in the resolver network, then on to the diverter valve, (containedin the pressure reducing manifold) where it is blocked at the diverter valve.

If the ripper lift cylinders reach the end of their stroke in either direction, or if external forcescause the ripper lift cylinders to move up, the lift relief valve will open to protect the rippercircuit from undue high pressures.


128

Shown above is a color schematic of the D10T implement hydraulic system in the RIPPERSHANK IN condition. Refer to illustration No. 129 to see the state of the ripper control valvecomponents during the following explanation of the ripper raise circuit.

When the operator moves the ripper shank control from HOLD to SHANK IN, a signal is sent tothe Implement ECM. The Implement ECM in turn sends a signal to energize the solenoids forthe ripper SHANK IN pilot valve and the PCO pilot valve on the EH pilot manifold (HPSI andHPRV). The ripper SHANK IN pilot valve then directs pilot oil to shift the raise spool to theright, into the SHANK IN position. The PCO valve directs pilot oil to shift the shuttle valvedown, which directs high pressure pump supply oil into the passage between the lift dump valveand the lift relief valve (in the dozer valve). The high pressure oil in this passage plus the forceof the spring keeps the dump valve in the closed position so that maximum oil pressure isavailable to move the ripper cylinders. The lift relief valve is also available to be used as therelief valve for the ripper circuit.



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129

The high pressure oil from the implement pump then flows past the internal load check valveand the ripper tip spool, and then out through the head end passages to the ripper lift cylinders.This causes the ripper cylinder rods to extend and the tip of the ripper shank moves in.

As the ripper tip cylinder rods extend, rod end oil from the ripper tip cylinders flows back to theripper control valve through the rod end passages in the control valve. This return oil flows pastthe ripper tip spool and into the tank passage and then returns to the hydraulic oil tank.


The ripper tip circuit has no connection to the resolver network.

If the ripper tip cylinders reach the end of their stroke in either direction, or if external forcescause the shank to move in or out, the lift relief valve will open to protect the ripper circuit fromundue high pressures.


Pilot Supply(Ripper Lower)

Pilot Supply(Shank Out)

Pilot Supply(Shank In)

Pilot Supply(Ripper Raise)

D10T RIPPER CONTROL VALVESHANK IN

Load CheckValve

Ripper Raise Spool

RipperTip Spool

Tank PassagePassage to Rod End

Passage to Head End

Tank Passage

Passage toHead End

Passage toRod End

Plug orRipper Warming

Valve

Pump Inlet (Combined)

130

Dual Tilt Operation

For machines equipped with dual tilt, the dual tilt valve (1) is mounted to the inside of theradiator guard, behind the left grill door. A second tilt cylinder is installed on the left side of theblade. The dual tilt valve is installed between the tilt control valve and the two tilt cylinders inthe dual tilt circuit. The rod end passage and the head end passage designation of the tilt controlvalve are reversed from the single tilt configuration. The dual tilt valve allows the operator totilt the blade right and left to a greater degree than single tilt, pitch the blade forward (dump),and rack the blade back.Service points identified in the above illustration are:

2. high pressure supply/return from/to blade tilt control valve (depending on tilt direction)3. case drain line4. pilot supply line (from the RATAAC fan speed control valve)5. dual tilt solenoid6. high pressure supply/return from/to blade tilt control valve (depending on tilt direction)7. high pressure lines to the left tilt cylinder8. high pressure lines to the right tilt cylinder

Auto Blade Assist (ABA) is standard on machines equipped with dual tilt.


1

2

3

4

5

6

7

8

131

The dual tilt valve has three modes of operation. They are:- DUAL TILT- SINGLE TILT- BLADE PITCH

Oil from the rear section of the implement pump is used as pilot oil to control the dual tilt valvespool. The pilot oil is controlled by a dual action solenoid valve. The dual action solenoidvalve has two coils - a "tilt coil" and a "pitch coil."When the thumb switch on the dozer control lever is moved to the right or to the left, the pitchsolenoid coil is ENERGIZED and the solenoid valve directs pilot oil to the bottom of the dualtilt valve spool, moving the spool up. The blade will then PITCH FORWARD or RACK BACK,depending on which direction the switch is moved.When the trigger switch on the dozer control lever is depressed, the tilt solenoid coil isenergized (when the default tilt mode is set to DUAL TILT) and the solenoid valve directs pilotoil to the top of the dual tilt valve spool, moving the spool down. If the default tilt mode is setto SINGLE TILT, the tilt solenoid coil is always ENERGIZED. The trigger switch will thentoggle to the DUAL TILT mode when the switch is depressed and the tilt coil is then DE-ENERGIZED. (The default tilt mode can be set using Cat Advisor.)


From TiltControl Valve

To TiltControl Valve

Tilt Coil fromTrigger Switch

Pitch Coil fromThumb Switch

Left TiltCylinder

Right TiltCylinder

DUAL TILT VALVEDUAL TILT RIGHT

Pilot Supply

To Head End

To Rod End

Illustration 131 shows the dual tilt valve in the DUAL TILT RIGHT condition. This is thedefault mode of operation unless the operator has set the default tilt mode to single tilt, usingCat Advisor. In the dual tilt mode, the tilt solenoid coil is always DE-ENERGIZED and the dualtilt spool remains centered by the springs on either end of the spool.

When the operator moves the dozer control lever to the right, commanding the TILT RIGHTfunction, the tilt control valve operates in the fashion described earlier in this presentation. Thepump supply oil from the head end passage of the blade tilt control valve flows out to the headend of the left tilt cylinder. The left tilt cylinder rod extends and forces the left tilt cylinder rodend oil out to the dual tilt valve. The left cylinder rod end oil flows around the dual tilt spooland out to the rod end of the right tilt cylinder. The right tilt cylinder rod retracts. The right tiltcylinder head end oil is then forced out, back to the dual tilt valve where it flows around the dualtilt spool and returns to the rod end passage of the blade tilt control valve as return oil.

The blade tilts right when the left tilt cylinder rod extends and the right tilt cylinder rod retracts.

For DUAL TILT LEFT, the flow of oil through the tilt circuit is reversed. In the DUAL TILTLEFT condition, the left tilt cylinder rod retracts and the right tilt cylinder rod extends.

The status of the dual tilt solenoid, the dozer control lever tilt position sensor, the rotary thumbswitch (position sensor) on the dozer control lever, and the trigger switch on the dozer controllever may be viewed through the Advisor panel (Service/System Status/Implement screens) orby using Cat ET.

NOTE: For information about how to set the default tilt mode for the dual tilt valve,refer to the "Caterpillar Monitoring and Display System with Advisor for Track-typeTractors," STMG 790 (Form No. SERV1790).


132

Illustration 132 shows the dual tilt valve in the SINGLE TILT RIGHT condition. If dual tilt hasbeen selected as the default tilt mode, the operator must depress and hold the trigger switch totoggle to SINGLE TILT mode. The operator may also set SINGLE TILT as the default tilt modeusing the Advisor panel. Either condition results in the tilt solenoid coil being ENERGIZED andthe solenoid valve directs pilot oil to the top of the dual tilt spool, moving the spool down. Withthe dual tilt spool in this position, the right tilt cylinder is isolated from the circuit and acts as abrace to provide the mechanical leverage needed to tilt the blade.

When the operator moves the dozer control lever to the right, commanding a TILT RIGHTfunction in the SINGLE TILT mode, pump supply oil from the head end passage of the blade tiltcontrol valve flows out to the head end of the left tilt cylinder. The left tilt cylinder rod extendsand forces the rod end oil back to the dual tilt valve. The left cylinder rod end oil flows aroundthe dual tilt spool. With the spool shifted down, the passages to the right tilt cylinder are blocked,but the passage back to the blade tilt control valve is open. The left tilt cylinder rod end oil flowsback to the rod end passage of the blade tilt control valve and returns to the tank.

When the left tilt cylinder rod extends and the right tilt cylinder remains stationary, the bladeTILTS RIGHT, but the angle of the tilt is not as acute as in the dual tilt mode.

For SINGLE TILT LEFT, the flow of oil through the tilt circuit is reversed. In the SINGLE TILTLEFT condition, the left tilt cylinder rod retracts and the right tilt cylinder remains stationary.




Left TiltCylinder

Right TiltCylinder

DUAL TILT VALVESINGLE TILT RIGHT

To Head End

To Rod End

Pilot Supply



133

Illustration 133 shows the dual tilt valve in the PITCH FORWARD condition. To pitch theblade forward, the operator must move the thumb rocker switch on the dozer control lever to theright (away from the operator). This results in the pitch solenoid coil being ENERGIZED andthe TILT LEFT pilot valve solenoid being ENERGIZED. The pitch solenoid valve directs pilotoil to the bottom of the dual tilt spool, moving it up.

When the operator has commanded a PITCH FORWARD function, pump supply oil from thehead end passage of the blade tilt control valve flows to the head end of the left tilt cylinder.The left tilt cylinder rod extends and forces the left tilt cylinder rod end oil to the dual tilt valve.The left cylinder rod end oil flows around the dual tilt spool. With the spool shifted up, the oilflows through the passage to the head end of the right tilt cylinder. The right tilt cylinder rodextends also, forcing the right tilt cylinder rod end oil to the dual tilt valve. The right tiltcylinder rod end oil then flows through the blade tilt control valve and returns to the tank.

Since the volume of rod end oil in the left tilt cylinder is less than the capacity of the head end ofthe right tilt cylinder, the left cylinder rod will fully extend before the right tilt cylinder head isfilled with oil. When the left tilt cylinder reaches its full extension, the bypass valve will openand oil will continue to flow to the head end of the right tilt cylinder. This results in the left tiltcylinder reaching its full extension slightly before the right tilt cylinder.


To Head End

To Rod End

Pilot Supply



Left TiltCylinder

Right TiltCylinder

DUAL TILT VALVEBLADE PITCH FORWARD



When the left and the right tilt cylinder rods extend, the blade will PITCH FORWARD.

To RACK BACK the blade, the operator must move the thumb rocker switch on the dozercontrol lever to the left (toward the operator). The flow of oil through the tilt circuit is reversed.In the RACK BACK condition, both the left and the right tilt cylinder rods retract.

When the left and the right tilt cylinder rods retract, the blade will RACK BACK.

INSTRUCTOR NOTE: When the thumb rocker switch on the dozer control lever ismoved to the PITCH FORWARD position, the TILT RIGHT solenoid controlled pilotvalve on the blade lift control valve is ENERGIZED to send pump supply oil to the dualtilt valve. When the thumb rocker switch on the dozer control lever is moved to theRACK BACK position, the TILT LEFT solenoid controlled pilot valve on the blade liftcontrol valve is ENERGIZED to send pump supply oil to the dual tilt valve.

NOTE: Machines equipped with dual tilt are also equipped with the Auto Blade Assist(ABA) feature. Blade positions for ABA are LOAD, CARRY, and SPREAD (or DUMP).All three of these functions automatically activate the dual tilt valve and the tilt controlvalve and will PITCH FORWARD or RACK BACK the blade to preset positions. Thesepositions can be adjusted using Cat Advisor. Briefly, these three blade positions aredefined as:

- LOAD position is when the dozer blade is pitched slightly forward for an aggressivecutting edge angle to LOAD the blade.

- CARRY position is when the dozer blade is racked back in a fully retracted, non-aggressive cutting edge angle so that the blade tends to CARRY material.

- SPREAD position is when the dozer blade is pitched fully forward to quickly and cleanlyempty the dozer blade and SPREAD the material.

The blade may be raised and lowered manually during these automatic cycles withoutinterrupting the cycles.


134

Quick-Drop Valve Operation

Two quick-drop valves are used on the D10T. One quick-drop valve is installed on top of eachblade lift cylinder. The quick-drop valves allow the bulldozer blade to drop rapidly to the groundwhen the dozer control lever is moved forward to approximately 80% of the control levermovement. The quick-drop valves help prevent cavitation in the head-ends of the blade liftcylinders by directing rod end return oil into the head ends of the cylinders during quick-dropmode. The quick-drop valves also help to minimize the pause time after the blade hits the groundand before full down pressure is exerted. All oil flow to and from the blade lift cylinders must gothrough the quick-drop valves.

The quick-drop valves are activated when a sufficient pressure difference occurs between thecylinder rod end oil and the oil in the spring cavity. This pressure difference is caused by rod endoil flow through an orifice in the quick-drop valve. The quick-drop valve is de-activated by highpressure in the head end felt through a slot in the spool. The quick-drop valves help control fourfunctions of the bulldozer: RAISE, LOWER at slow speeds, rapid LOWER (quick-drop), andLOWER with down pressure.

These are the same type of quick-drop valves used on the D10R machine.


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135

When the dozer control lever is moved from HOLD to a RAISE position, supply oil from thedozer control valve enters the quick-drop valve through the rod end inlet passage. The oil flowsthrough the large orifice and is then directed to the rod end of the lift cylinder. A small amountof oil also flows through the small orifice and fills the spring chamber behind the plunger. Oilalso flows through a small passage in the spool and fills the chamber at the right end of thespool.

The pressure of the oil in the spring chamber adds to the force of the spring. The combinedpressure and spring force pushes the plunger to the right, against the valve spool. The force ofthe plunger is greater than the oil pressure at the right end of the valve spool, so the spoolremains shifted to the right. This condition causes all the of oil entering the quick-drop valve tobe directed to the rod ends of the lift cylinders and all the of oil from the head ends of the liftcylinders to return to the tank through the head end passage of the quick drop valve and thenthrough the dozer control valve.


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136

When the dozer control lever is moved to a BLADE LOWER position that is less thanapproximately 80% of full lever travel, the lowering of the blade is controlled. The flow of oilthat can pass through the dozer control valve at any given spool position is a function of thepressure difference across the spool and the temperature of the oil.

As stated earlier, the quick-drop valve is activated by high oil flow from the lift cylinder rod endin combination with low lift cylinder head end pressure. For this reason, the actual position ofthe control lever when the quick-drop valve is actuated can vary based on oil temperature andthe weight of the blade.

When the dozer control lever is moved to a controlled LOWER position, supply oil from thedozer control valve enters the quick-drop valve through the head end inlet and flows through thepassage to the head end of the lift cylinders.

The oil being forced from the rod end of the cylinders returns through the quick-drop valve andthen through the dozer control valve to the tank. Because of the weight of the blade and theresistance to oil flow through the quick-drop valve and the control valve, the pressure of the rodend oil may be higher than that of the head end oil.


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The flow of cylinder rod end oil through the quick-drop valve's large orifice and also through itssmall orifice (into the spring chamber) is not high enough to create a large pressure differencebetween the oil in the rod end inlet passage and the oil behind the plunger. The spring force andoil pressure in the spring chamber is still greater than the oil pressure at the right of the spool.This keeps the plunger and the valve spool shifted to the right and all of the oil leaving the rodend of the lift cylinder returns through the dozer control valve to the hydraulic tank.


137

When the dozer control lever is moved forward to a position that exceeds approximately 80% oflever travel and the blade is raised above the ground, the cylinder head end pressure is lowerthan the rod end pressure, and the quick-drop valve is activated. The blade will drop veryrapidly until it contacts the ground. The oil flow for a quick-drop is the same as the controlledlower except that some of the oil leaving the rod end of the lift cylinder is directed into the headend of the cylinder.

When the flow of rod end oil through the large orifice is high enough, the large orifice restrictsthe oil flow to the dozer control valve. The pressure of the oil flowing through the small orificeinto the spring chamber is the same pressure as the oil returning to the dozer control valve. Thiscreates a large pressure differential between the rod end oil at the right end of the valve spooland the combined oil pressure and spring force at the left end of the plunger. The valve spooland plunger will shift to the left and permit oil leaving the rod end to supplement the supply oilfilling the head end of the lift cylinders.

As stated earlier, during a rapid blade drop, the rod end pressure will be higher than the head endpressure due to the blade weight. The resulting pressure differential and valve movement allowsthe rod end oil to flow to the head end of the cylinder and helps minimize cylinder voiding.


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138

When down pressure must be applied to the blade, the operator moves the dozer control leverforward to the LOWER position. High pressure supply oil from the dozer control valve flowsinto the quick-drop valve through the head end inlet passage and is sent to the head end of thelift cylinders.

At the same time, this high pressure supply oil fills the chamber at the left end of valve spools.The head end pressure of the supply oil increases as the resistance to downward movementincreases. The flow of oil from the rod end of the lift cylinder is near tank pressure, as is thepressure of the oil at the right end of the valve spool. The flow of oil returning through the largeorifice and the oil returning to the dozer control valve are also near tank pressure. This causesthe oil pressure in the spring chamber at the left end of the plunger to also be near tank pressure.

Since the pressure in the chamber at the left end of the valve spool is greater than the pressure atthe right end, the valve spool shifts to the right. The pressure at the right end of the plunger isless than the combined pressure and spring force at the left end of the plunger, so the plunger isshifted to the left against the force of the spring. In this condition, all of the oil from the dozercontrol valve is then sent to the head end of the lift cylinders and all the rod end oil is returnedthrough the dozer control valve to the tank.


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139

AutoCarry

For machines equipped with AutoCarry, there are three major components included in theimplement system (not including software and wiring harnesses). These components are:

- dozer lift cylinder position sensor (right lift cylinder only)- dynamic inclination sensor- ground speed radar

The illustration above shows the lift cylinder position sensor (1) installed on the top of the rightdozer lift cylinder. This sensor provides a feedback signal to the Implement ECM. TheImplement ECM uses this information to determine how much the lift cylinder piston moveswhen cylinder movement is automatically commanded by the Implement ECM during theCARRY segment of the AutoCarry cycle.

The wiring harness for the position sensor is attached at the connector (2). The lift cylinderposition sensor replaces the right quick-drop valve. The oil from both lift cylinders passesthrough the quick-drop valve when the quick-drop mode is invoked.

There is a calibration routine for the lift cylinder position sensor. It may be performed byaccessing the Blade Calibrations within the Service option of Cat Advisor, or by using Cat ET.


1

2

A dynamic inclination sensor (1) is another component present on machines equipped withAutoCarry. The dynamic inclination sensor (illustration No. 140) is installed to the left of theEH pilot manifold, on top of the main case. The dynamic inclination sensor determines theangle of incline on which the machine is operating. It transmits that information to theImplement ECM. This data is used when determining blade height adjustments during the Carrysegment of the AutoCarry cycle.

Also present on machines with AutoCarry is the Ground Speed Radar (2), as shown inillustration No. 141. This component is mounted to a bracket that is attached to the bottom ofthe drive shaft guard. The radar senses actual ground speed through an opening in the bottomguard (3).

140

141


1

2

3

The ground speed signal is sent to the Implement ECM. Actual ground speed is compared to thetarget ground speed (considering torque converter output speed and the slope on which themachine is operating). This information is used by the Implement ECM when making bladeheight adjustments during the "Carry" segment of the AutoCarry cycle, ensuring maximumdozing cycle efficiency. Ground speed is compared to the "target speed" to determine theamount of track slippage during the CARRY segment of the AutoCarry cycle.

The Implement ECM calculates "Target speed" by considering the following variables:- the torque converter output speed sensor (from the Power Train ECM);- the angle of inclination on which the machine is operating (from the dynamic inclination

sensor); and- the Load Factor setting (which is an "offset" setting that the operator can adjust using Cat

Advisor).

All of this information is used by the Implement ECM (which contains the AutoCarry software)to make automatic adjustments to blade height during the CARRY segment of the AutoCarrycycle.

If the Implement ECM determines that the tracks are slipping too much (considering allvariables), the Implement ECM will automatically operate the blade lift control valve to raiseand/or lower the blade until the target speed is once again attained. This strategy ensures thatthe optimum amount of material is kept in the blade during the CARRY segment. This results inimproved efficiency when pushing material over long distances, and ensuring maximum dozingcycle efficiency. (Dozing cycle efficiency refers to the amount of material moved per gallon offuel consumed.)

NOTE: During the AutoCarry cycle, the transmission operation will be limited to FIRST GEAR FORWARD and FIRST GEAR REVERSE.


142

The diverter valve (1) is a component that is present on the D10T if the machine is equippedwith AutoCarry. It is mounted to the front of the main case, to the right of the drive shaft.

The diverter valve is solenoid operated. Its purpose is to divert all of the pump flow from thelarge (front) section of the implement pump (lift pump) back to the tank during the CARRYsegment of the AutoCarry cycle. The purpose of this strategy is to prevent overheating thehydraulic oil when using AutoCarry.

The Implement ECM constantly makes automatic adjustments to the blade height during theCARRY segment. The combined flow of both the lift pump and the tilt pump creates too muchheat in the hydraulic system when the dozer valve is being constantly manipulated during theCARRY segment of the AutoCarry cycle. Only the tilt pump is supplying oil to the dozer valve,with all the flow from the lift pump diverted to the tank. The reduced flow through the dozervalve during automatic valve manipulation creates less heat in the hydraulic oil system.

The diverter valve solenoid (2) and a pressure test port (3) for HPD3 are located on the front ofthe diverter valve. The HPD3 pressure test port will allow the serviceman to test the hydraulicoil pressure in the lift pump circuit when the solenoid is either energized or de-energized. Whenthe diverter valve solenoid is DE-ENERGIZED, HPD3 pressure should be equal to HPD1.


1

2

3

143

The AutoCarry cycle has six distinctive segments that position the blade height and blade pitchautomatically. The segments are invoked by pushing the left yellow button on the dozer controllever and/or by shifting the transmission from FORWARD to REVERSE and back toFORWARD. These six AutoCarry segments are:

- READY TO CARRY (blade is pitched to the LOAD position - aggressive cutting angle)- CARRY (blade is racked back to the CARRY position - less aggressive cutting angle)- SPREAD (blade automatically pitches all the way forward to DUMP the blade contents)- READY TO RETURN (blade pitch all the way forward and is at the end of stroke)- RESETTING (blade raises to top of lift cylinder stroke during REVERSE direction)- RETURN (blade height returns to ground level and pitches forward to LOAD position)

During the CARRY segment, the Implement ECM constantly makes numerous automaticadjustments to the blade height due to changes in the operating incline and variations in groundspeed. The combined flow of both the lift pump (front section) and the tilt pump (middlesection) creates too much heat in the hydraulic system when the dozer valve is being constantlymanipulated. This is due to the high volume of oil that flows through the dozer lift circuit, theorifice effect of the blade lift spool when it opens and closes, and the flow of oil throughpassages to the dump valve and other components in the dozer control valve.


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The diverter valve helps reduce heat by dumping the entire flow from the lift pump directly backto the hydraulic oil tank.

Illustration No. 143 shows the implement hydraulic system in a condition during the CARRYsegment when the Implement ECM is commanding an automatic BLADE RAISE function.

When the blade is in the LOAD position and the operator determines that the blade is full ofmaterial, the operator must push the left yellow button on the dozer control lever to invoke theCARRY segment of the AutoCarry cycle. The Implement ECM will then automatically rack theblade back to the preset CARRY position. In this position, the cutting angle of the blade is lessaggressive and will serve to push the material already in the blade. The Implement ECM willthen automatically make adjustments to the blade height in order to compensate for changes inground slope and when the actual ground speed falls below the target ground speed.

When the Implement ECM initiates the CARRY segment of the AutoCarry cycle, it alsoenergizes the solenoid operated pilot valve on the diverter valve. The pilot valve then directspilot oil to the bottom of the pilot operated diverter valve spool, shifting it up against the spring.In this position, the diverter valve spool directs the flow of high pressure oil from the lift pumpback to the hydraulic oil tank. The diverter valve spool also blocks the flow of oil from thedozer lift circuit that is now filled with oil exclusively by the tilt pump, through the open-centertilt valve spool.

When the next segment in the AutoCarry cycle is invoked, the pilot valve solenoid on thediverter valve is DE-ENERGIZED and normal pump flow and operation of the dozer lift circuitis resumed.


144

ELECTRICAL SYSTEM

The illustration above shows a graphical representation of the The Caterpillar Monitoring andDisplay System for the D10T Track-type Tractor. The hardware components in the systeminclude Cat Advisor, the instrument cluster, the Engine ECM, the Implement ECM, the PowerTrain ECM, the Action Alarm, the rear Action Lamp, and various switches, sensors and senders.The illustrations on the following pages show the engine, the power train, and the implementelectrical systems. They also identify all of the switches, the sensors, the senders, and thesolenoids that are the input and the output devices used in each system. Depending on how themachine is equipped, some or all of these devices may be present. Also shown in theseillustrations is the means by which these components and systems communicate with each otherand how the information from the input and output devices is shared between systems.Communication of information on standard machines occurs through the following data links:

- Cat Data Link- CAN A Data Link (high speed)- CAN C Data Link (high speed)

With AutoCarry or other automated earthmoving attachments, the D10T will also include a CAN B Data Link (shown in dashed lines, above) and a CAN D Data Link (not shown) that isused to connect components in the CAES system or other automated earthmoving systems.


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Shown above is an illustration of the electrical system for the C27 ACERT engine used in theD10T Track-type Tractor.

The Engine ECM considers only the engine coolant temperature as an input for controlling thehydraulic demand fan.

To view the status of all the engine components shown above using Cat Advisor:

- select the "Service" option from the Home Menu to display the Service Menu- select "System Status" from the Service Menu to display the System Status Menu- select "Engine" from the System Status Menu- use the ARROW buttons to page through the list of components

Cat ET may also be used to view the status of these components.

Since the timing calibration probe is permanently installed in the flywheel housing, theserviceman need only invoke the timing calibration routine using Cat ET to perform thatoperation.


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146

Shown above is an illustration of the electrical system for the D10T Track-type Tractor powertrain system.

The Power Train ECM determines engine lug and torque curves by comparing engine speed datato the torque converter output speed data. The Power Train ECM uses this information todetermine when to automatically downshift the transmission for the Auto KickDown feature.Since the D10T does not have an engine output speed sensor, the primary (crankshaft)speed/timing sensor provides engine speed data to the Engine ECM, which shares that data withthe Power Train ECM through the CAN A Data Link.

To view the status of all the power train components shown above using Cat Advisor:- select the "Service" option from the Home Menu to display the Service Menu- select "System Status" from the Service Menu to display the System Status Menu- select "Powertrain" from the System Status Menu- use the ARROW buttons to page through the list of components

Cat ET may also be used to view the status of these components. Calibrations for the powertrain system (transmission, brakes, etc.) may be performed through the Advisor panel, or byusing Cat ET.


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Shown above is an illustration of the electrical system for the D10T Track-type Tractorimplement hydraulic system.

The Implement ECM requires torque converter output speed data to determine track speed, if themachine is equipped with AutoCarry. Track speed is determined by a calculation using torqueconverter output speed sensor data. The Power Train ECM monitors this sensor and shares thisinformation with the Implement ECM through the CAN A Data Link. The Implement Lockoutswitch is automatically DE-ENERGIZED by the Implement ECM when engine speed is below900 rpm. The Engine ECM shares the engine speed information (from the crank speed/timingsensor) with the Implement ECM to accomplish this strategy.

To view the status of all the implement hydraulic system components shown above using CatAdvisor:

-select the "Service" option from the Home Menu to display the Service Menu-select "System Status" from the Service Menu to display the System Status Menu-select "Implement" from the System Status Menu-use the ARROW buttons to page through the list of components

Cat ET may also be used to view the status of these components.


Torque ConverterOutput Speed

Sensor

Tilt PumpPressure Sensor

Harness Code PlugLocat ion Code

Hydraulic OilTemp. Sensor

Shank InSolenoid

Blade RaiseSolenoid

Blade Tilt RightSolenoid

Blade LowerSolenoid

Blade Tilt LeftSolenoid

Dual TiltSolenoid

(At tachment)

Shank OutSolenoid

Diverter ValveSolenoid

Implement LockoutSolenoid

Ripper RaiseSolenoid

Ripper LowerSolenoid

Blade ManualSelect Switch

(Right Push-But ton)

Key StartSwitch

Auto CarrySwitch

(At tachment)

Auto BladeAssist Switch(At tachment)

ImplementLockoutSwitch

Blade ModeSelect Switch

(Left Push-But ton)

Blade Raise / LowerPosit ion Sensor

(Forward / Rearward)

Ripper Tip In / OutPosit ion Sensor

(Control Handle)

Ripper Auto StowSwitch

Blade Pitch / AnglePosit ion Sensor(Thumb Switch)

INPUT COMPONENTS OUTPUT COMPONENTS

Ripper Raise / LowerPosit ion Sensor

(Control Handle)

Advisor

Blade TiltPosit ion Sensor

(Left / Right )

Dual/ Single Tilt ToggleTrigger Switch

Ripper ControlHandle

Blade ControlLever

ImplementHydraulics

ECM

Crank SpeedSensor

Right Lift CylinderPosit ion Sensor(At tachment)

Lift PumpPressure Sensor

Hydraulic Oil FilterBypass Switch

PCO ValveSolenoid

Power TrainECM

Ground SpeedRadar

J2 J1

CAT Data Link

CAN A Data Link

EngineECM

INPUT COMPONENTS

D10T IMPLEMENT HYDRAULICS ELECTRICAL SYSTEM

148

CONCLUSION

This presentation has discussed locations of components and the systems operation of theengine, the cooling system, the power train, the implement hydraulics, the electrical system, andthe Caterpillar Monitoring and Display System (Advisor) for the D10T Track-type Tractor.

When used in conjunction with the Service Manual and the STMG 790, "Caterpillar Monitoringand Display System with Advisor for Track-type Tractors," the information in this package willhelp the serviceman analyze problems in any of the major systems of the D10T Track-typeTractor.


HYDRAULIC SCHEMATIC COLOR CODE

This illustration identifies the meanings of the colors used in the hydraulic schematics and cross-sectional views shown throughout this presentation.


Red - High Pressure Oil

Red / White Stripes - 1st Pressure Reduction

Pink - 3rd Reduction in Pressure

Red / Pink Stripes - Secondary Source Oil Pressure

Orange - Pilot, Signal or Torque Converter Oil

Blue - Trapped Oil

Brown - Lubricating Oil

Cat Yellow - (Restricted Usage)

Green / White Stripes -Scavenge / Suction Oil or Hydraulic Void

Identification of Componentswithin a Moving Group

HYDRAULIC SCHEMATIC COLOR CODE

Black - Mechanical Connection. Seal

Dark Gray - Cutaway Section

Light Gray - Surface Color

White - Atmosphere Or Air (No Pressure)

Purple - Pneumatic Pressure

Yellow - Moving or Activated Components

Orange / Crosshatch - 2nd Reduction inPilot, Signal or TC Oil Pressure

Orange / White Stripes - Reduced Pilot, Signal orTC Oil Pressure

Red Crosshatch - 2nd Reduction in Pressure

Green - Tank, Sump, or Return Oil

VISUAL LIST

STMG 800 - 193 - Visual List03/05

42. Oil coolers and coolant flow switch43. Timing calibration probe44. Front gear train - cover removed45. Rear gear train - cover removed46. Turbo oil and coolant lines47. Fuel heater48. Fuel level sensor49. Fuel system schematic50. Engine air system components51. Cooling system schematic52. Cooling system components53. Hydraulic oil cooler54. Fan and hydraulic demand fan motor55. Coolant fill tube/cap and sight glass56. Standard fan system schematic - Max speed57. Standard fan system schematic - Min speed58. Fan pump color cutaway - Max fan speed59. Fan pump color cutaway - Min fan speed60. Fan system schematic - fan reverse/bypass61. Fan system schematic- fan reverse active62. Fan system schematic- fan bypass active63. Fan pump components ID and location64. Fan motor components ID and location65. Fan reversing/bypass valve location and ID66. RATAAC system schematic67. RATAAC components - hood top68. RATAAC components - under hood69. RATAAC heat exchanger cores70. RATAAC pump and fan speed control valve71. Power train component location diagram72. Power Train Electronic Control System73. Power train hydraulic schematic74. Power train major components location75. Power train oil pump76. Power train filters, brake valve location77. Transmission charge filter components78. Torque converter charge filter components79. Rear power train pressure test ports80. TC inlet relief valve/lube distribution man.81. Torque converter inlet relief valve operation82. Torque divider and components ID/location

1. Title slide2. Operator compartment view3. Left console controls - front view4. Left console controls - overhead view5. Right console6. Dozer control lever7. Ripper control handle8. Machine function switches - right console9. Fuse panel and Cat ET comm port

10. HVAC and wiper/washer controls11. Dash12. Brake pedal and decelerator pedal13. Power Train and Implement ECMs14. Monitoring system components view15. Monitoring system components ID16. Instrument cluster ID17. Advisor panel18. Advisor panel components ID19. Advisor Start-Up screen20. Advisor warning screen21. Advisor Performance 1 of 2 screen22. Advisor Performance 2 of 2 screen23. C27 ACERT engine section title slide24. C27 left side engine view25. C27 right side engine view26. Primary fuel filter27. Fuel transfer pump and pressure regulator28. Secondary fuel filter components ID29. Engine oil filters30. Engine sensors - overhead engine view31. Primary (crank) speed/timing sensor32. Starter (left side) and block heater element33. Engine oil ecology drain valve34. Engine pre-lube pump35. Electrical disconnects36. Ether aid and solenoid37. C27 engine front view38. A4 Engine ECM39. Engine oil pressure sensor - cam sensor40. Turbo inlet pressure sensor41. Crank Without Inject connector/plugs

VISUAL LIST

STMG 800 - 194 - Visual List03/05

83. Torque divider cutaway84. Torque converter outlet relief valve85. Torque converter outlet relief valve operation86. Power train oil coolers87. Power shift trans. - removed from case88. Transmission output speed sensors89. Transmission modulating valve operation90. Transmission main relief valve operation91. Transmission main relief valve92. Power shift transmission cutaway93. Electronic steering/brake control valve94. Steering/brake control valve cutaway95. Steer/brake valve operation - released96. Steer/brake valve operation - engaged97. Steer/brake valve operation - park engaged98. Steer/brake valve operation - grad. rt. turn99. Steer/brake valve operation - sharp rt. turn

100. Power train oil fill tube and dipstick101. Power train breather location102. Brake lube/brake pressure taps (final drive)103. Brake pedal position sensor104. High-Speed power train oil change port105. Ripper pin puller solenoid and valve106. Imp. hydraulic system component location107. Implement hydr. - major components ID108. Hydraulic oil tank component ID109. Implement pump component ID110. Dozer valve components ID111. Ripper valve components ID112. Hydraulic oil cooler bypass valve location113. Pressure reducing manifold compon. ID114. Pressure reducing manifold schematic115. Pilot oil filter location and ID116. EH pilot manifold location and ID117. EH pilot manifold operation118. Dozer control valve cutaway - front view119. Dozer control valve cutaway - side view120. Hydraulic schematic - blade raise121. Hydraulic schematic - blade float122. Dozer control valve cutaway - front float123. Hydraulic schematic - tilt left/single tilt

124. Tilt control valve cutaway - tilt left125. Hydraulic schematic - tilt left/dual tilt126. Ripper valve cutaway - ripper raise127. Hydraulic schematic - ripper raise128. Hydraulic schematic - ripper shank in129. Ripper valve cutaway - shank in130. Dual tilt valve component ID131. Dual tilt valve cutaway (dual tilt right)132. Dual tilt valve cutaway (single tilt right)133. Dual tilt valve cutaway (blade pitch fwd.)134. Quick-drop valve circuit (schematic)135. Quick-drop valve cutaway (dozer raise)136. Quick-drop valve cutaway (dozer lower)137. Quick-drop valve cutaway (quick-drop)138. Quick-drop valve cutaway (down pressure)139. Lift cylinder position sensor140. Dynamic inclination sensor141. Ground speed radar142. AutoCarry diverter valve143. Hydr. schem. - AutoCarry active-blade raise144. Monitoring system/electrical schematic145. C27 engine electrical components146. Power train electrical components147. Implement hydraulics electrical components148. D10T rear view - conclusion

Engine System Components Identification

Directions: Use this sheet to take notes during the presentation. During the lab exercise, usethis sheet as a checklist when locating and identifying the components.

STMG 800 - 195 - Handout No. 103/05

Engine Components

____ Primary and Secondary fuel filters

____ Electric fuel priming pump and switch

____ Fuel transfer pump

____ Engine oil fill tube and dipstick

____ Engine oil filters

____ Engine oil S•O•S test port

____ Engine oil pressure test port

____ Engine oil pressure sensor

____ Engine pre-lube motor and pump

____ Engine oil cooler

____ Air filters

____ Turbochargers

____ AMOCS radiator and shunt tank

____ Engine coolant S•O•S test port

____ Jacket water pump

____ Temperature regulator housing

____ Main electrical disconnect switch

____ Starter Disconnect switch

____ A4 Engine ECM

____ Alternator

____ Ether injection control solenoid

____ Intake manifold air pressure sensors (2)

____ Atmospheric air pressure sensor

____ Intake manifold air temperature sensor

____ Fuel temperature sensor

____ Fuel pressure sensor

____ Fuel filter differential pressure switch

____ Turbo inlet pressure sensor

____ "Crank-without-Inject" connector/plug

____ Primary (crank) speed/timing sensor

____ Secondary (cam) speed/timing sensor

____ Starter

____ Coolant temperature sensor

____ Coolant flow switch

____ Timing calibration probe

____ Block heater element

____ Block heater AC power receptacle

____ Auxiliary start receptacle

Cooling System and Demand Fan System Components Identification

Directions: Use this sheet to take notes during the presentation. During a lab exercise, use thissheet as a checklist when locating and identifying the components.

STMG 800 - 196 - Handout No. 203/05

Cooling System Components

____ Engine oil cooler

____ Power train oil coolers

____ Jacket water pump

____ AMOCS radiator cores

____ Water temperature regulator housing

____ Coolant shunt tank

____ Coolant fill tube and cap

____ Coolant level sight glass

____ Cooling system drain valve

____ RATAAC cores

____ RATAAC fan motor

____ RATAAC fan pump

____ RATAAC fan speed control valve

____ Hydraulic Fan Pump Discharge pressuretest port (HFPD)

____ Hydraulic Fan Motor Inlet pressure testport (HFMI)

Demand Fan System Components

____ Hydraulic demand fan pump

____ Fan pump control valve

____ Fan pump pressure control solenoid

____ Fan pump discharge pressure sensor

____ Hydraulic Fan Pump Discharge pressuretest port (HDFP)

____ Fan motor

____ Fan reversing/bypass valve (if equipped)

____ Manual fan reversing switch (if equipped)

____ Engine coolant temperature sensor

____ A4 Engine ECM

Power Train Components Identification


STMG 800 - 197 - Handout No. 303/05

Power Train Components

____ Power Train ECM

____ Power train oil pump

____ Power train oil fill tube and dipstick

____ Power train lube distribution manifold

____ Torque converter inlet relief valve

____ Torque converter outlet relief valve

____ Torque converter outlet temp. sensor

____ Power train oil coolers

____ Transmission charging filter

____ Torque converter charging filter

____ Power train oil temperature sensor (sump)

____ Power train oil filter bypass switch

____ Torque converter output speed sensor

____ Electronic steering/brake control valve

____ Service brake pedal position sensor

____ Parking brake switch

____ Left and right steering lever positionsensors (FTC control lever sensors)

Power Train Pressure Test Ports

____ Torque converter outlet relief pressuretest port (N)

____ Cooler Lube pressure test port (CL)

____ Power train system lube pressure (L1)

____ Lube distribution manifold pressure (L2)

____ Torque converter inlet relief (supply)pressure test port (M)

____ Transmission main relief pressure test port (P)

____ Transmission pump pressure test port (TP)

____ Power train oil S•O•S port

____ Right brake lube pressure test port (LB2)

____ Left brake lube pressure test port (LB1)

____ Brake and steering clutch pressure test ports(B1/B2/C1/C2)

____ Right brake pressure test port (B2 - at final drive)

____ Right clutch pressure test port (C2 - at final drive)

____ Left brake pressure test port (B1 - at final drive)

____ Left clutch pressure test port (C1 - at final drive)

Hydraulic System Components Identification


STMG 800 - 198 - Handout No. 403/05

Implement Hydraulic Components

____ Hydraulic oil tank

____ Hydraulic oil fill tube and sight glass

____ Implement return oil filters (2)

____ Implement pump

____ Pressure reducing manifold

____ EH pilot manifold

____ Implement lockout solenoid valve

____ "Dead Electric" lower valve

____ Pilot oil filter

____ Dozer control valve

____ Ripper control valve

____ Lift pump pressure sensor

____ Tilt pump pressure sensor

____ Quick-drop valves

____ Dual tilt valve (if equipped)

____ Fan reversing valve (if equipped)

____ Implement ECM

____ Hydraulic oil cooler and bypass valve

____ Hydraulic oil temperature sensor

Implement Hydraulic Pressure Test Ports

____ Lift pump pressure test port (HPD1)

____ Tilt pump pressure test port (HPD2)

____ Hydraulic Fan Pump Discharge pressuretest port (HFPD)

____ Pilot supply pressure test port (HPS)

____ Pilot pressure test ports (9 ports, at EH pilot manifold)

____ Hydraulic oil S•O•S (fluid sampling) port

STMG 800 - 199 - Handout No. 5A03/05

MACHINE SYSTEMS POSTTESTUsing any of the provided classroom materials, demonstrate your knowledge of the variousmachine systems by circling the BEST ANSWER for each of following questions.

The C27 ACERT Engine

1. The atmospheric pressure sensor is used:A. to calculate boost pressure and air filter restrictionB. to determine ambient air pressure and as a reference for all other engine pressure sensors C. to calculate gauge pressure for engine oil and fuelD. all of the above answers (A, B, and C)E. answers A and C

2. The intake manifold air pressure sensor is used to:A. calculate boost pressureB. determine air filter restrictionC. determine RATAAC restrictionD. all of the above

3. The turbo inlet air pressure sensor is used to:A. calculate boost pressureB. determine air filter restrictionC. determine turbocharger failureD. answers A and B

4. The fuel transfer pump:A. draws fuel from the secondary fuel filterB. draws fuel from the primary fuel filterC. maintains fuel system pressureD. provides fuel flow through the entire fuel systemE. answers A, C, and DF. answers B and D

5. The fuel pressure regulator:A. maintains fuel system pressureB. is positioned between the fuel injectors and the fuel tankC. is positioned between the fuel injectors and the fuel transfer pumpD. answers A and BE. answers A and C

6. The primary (crank) speed/timing sensor:A. provides engine speed information to the Engine ECMB. provides engine speed information to the Power Train ECMC. is used to calculate shifting points for the Auto KickDown shifting strategyD. all of the above answers (A, B, and C)E. answers A and B

STMG 800 - 200 - Handout No. 5B03/05

MACHINE SYSTEMS POSTTEST (continued)Using any of the provided classroom materials, demonstrate your knowledge of the variousmachine systems by circling the BEST ANSWER for each of following questions.

The Hydraulic Demand Fan System

7. The sensors (inputs) used to control the hydraulic demand fan are:A. intake air temperature, coolant temperature, and fan pump discharge pressureB. intake air temperature and fan pump discharge pressureC. coolant temperature and fan pump discharge pressureD. hydraulic oil temperature, intake air temperature, coolant temperature, and fan pump

discharge pressure

8. When controlling the hydraulic demand fan, the Engine ECM:A. sends maximum current to the fan pump control solenoid to produce minimum speedB. sends minimum current to the fan pump control solenoid to produce maximum speedC. sends maximum current to the fan pump control solenoid to produce maximum speedD. sends minimum current to the fan pump control solenoid to produce minimum speedE. answers A and BF. answers C and D

9. The hydraulic demand fan may be shut OFF by:A. disconnecting the fan pump control solenoidB. using the Cat Advisor Configuration screen to turn fan control OFFC. using the Cat ET Configuration screen to turn fan control OFFD. answers B and CE. answers A and CF. none of the above

10. Maximum fan speed (high pressure cutoff) can be attained by:A. disconnecting the fan pump control solenoidB. using the Cat Advisor Configuration screen to turn fan control OFFC. using the Cat ET Configuration screen to turn fan control OFFD. answers A and BE. answers A and CF. none of the above

STMG 800 - 201 - Handout No. 5C03/05

MACHINE SYSTEMS POSTTEST (continued)Using any of the provided classroom materials, demonstrate your knowledge of the variousmachine systems by circling the BEST ANSWER for each of following questions.

The Power Train System

11. The Torque Converter Inlet Relief Valve:A. limits the maximum oil pressure to the torque converterB. limits the maximum oil pressure in the torque converterC. protects the components in the torque converter when the oil is coldD. answers A and CE. answers B and C

12. The Torque Converter Outlet Relief Valve:A. ensures a constant oil pressure to the torque converterB. maintains a constant maximum oil pressure inside the torque converterC. maintains a constant minimum oil pressure inside the torque converterD. limits the maximum temperature inside the torque converterE. answers C and D

13. The Transmission Main Relief Valve maintains the oil pressure:A. for the operation of the transmissionB. for the operation of the torque converterC. for the operation of the steering clutches and the brakesD. all of the above answersE. answers A and C

14. The steering clutches are:A. spring applied and hydraulically releasedB. hydraulically applied and spring releasedC. hydraulically applied and hydraulically released

15. The brakes are:A. spring applied and hydraulically releasedB. hydraulically applied and spring releasedC. hydraulically applied and hydraulically released

16. When the service brakes are FULLY APPLIED (ENGAGED) using the service brake pedal:A. the proportional brake valve solenoids are DE-ENERGIZED and the secondary brake

valve solenoid is ENERGIZEDB. the proportional brake valve solenoids are ENERGIZED and the secondary brake valve

solenoid is DE-ENERGIZEDC. the proportional brake valve solenoids are DE-ENERGIZED and the secondary brake

valve solenoid is DE-ENERGIZEDD. the proportional brake valve solenoids are ENERGIZED and the secondary brake valve

solenoid is ENERGIZEDE. none of the above answers

MACHINE SYSTEMS POSTTEST (continued)Using any of the provided classroom materials, demonstrate your knowledge of the implementsystem by entering the letter of the BEST ANSWER for each of the implement systemcomponents listed at the left.

The Implement Hydraulic System

STMG 800 - 202 - Handout No. 5D03/05

____ Hydraulic oil tank

____ Implement pump

____ Pressure reducing manifold

____ Implement lockout solenoid valve

____ Pilot oil filter

____ Dozer and ripper control valves

____ Lift dump valve

____ Tilt dump valve

____ Shuttle valve

____ Solenoid controlled pilot valve

____ Quick-drop valve

____ Implement ECM

____ Hydraulic oil cooler bypass valve

A. Direct the flow of high pressure pump supplyoil to the implement cylinders.

B. Ensures that clean oil is delivered to thesolenoid controlled pilot valves.

C. Opens to bypass the cooler when the hydraulicoil is cold and closes when the hydraulic oil iswarm to direct oil through the cooler.

D. Provides oil flow through the entire hydraulicsystem for the operation of the implements.

E. ENERGIZED by the Implement ECM to directpilot pressure oil to move an implement controlvalve spool.

F. Receives signals from implement control leversensors and sends corresponding currents to theappropriate solenoid controlled pilot valves.

G. Blocks the flow of pilot pressure oil to the EHpilot manifold when DE-ENERGIZED.

H. Directs rod-end oil from the blade lift cylindersinto the head-ends when the blade falls rapidlyto the ground.

I. Serves as a reservoir for the hydraulic oil.

J. Is closed by high pressure supply oil to shut offoil flow to tank when a blade lift or a ripperfunction is active.

K. Contains the pressure reducing valve and theDead Electric Lower valve.

L. Directs high pressure supply oil to the lift dumpvalve and the lift relief valve when a blade liftfunction is active.

M. Is closed by high pressure supply oil to shut offoil flow to tank when a blade tilt function isactive.

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STMG 800 - 203 - Handout No. 603/05

STMG 800 - 204 - Handout No. 5A03/05 Posttest Answers

MACHINE SYSTEMS POSTTEST ANSWERS Using any of the provided classroom materials, demonstrate your knowledge of the variousmachine systems by circling the BEST ANSWER for each of following questions.

The C27 ACERT Engine

1. The atmospheric pressure sensor is used:A. to calculate boost pressure and air filter restrictionB. to determine ambient air pressure and as a reference for all other engine pressure sensors C. to calculate gauge pressure for engine oil and fuelD. all of the above answers (A, B, and C)E. answers A and C

2. The intake manifold air pressure sensor is used to:A. calculate boost pressureB. determine air filter restrictionC. determine RATAAC restrictionD. all of the above

3. The turbo inlet air pressure sensor is used to:A. calculate boost pressureB. determine air filter restrictionC. determine turbocharger failureD. answers A and B

4. The fuel transfer pump:A. draws fuel from the secondary fuel filterB. draws fuel from the primary fuel filterC. maintains fuel system pressureD. provides fuel flow through the entire fuel systemE. answers A, C, and DF. answers B and D

5. The fuel pressure regulator:A. maintains fuel system pressureB. is positioned between the fuel injectors and the fuel tankC. is positioned between the fuel injectors and the fuel transfer pumpD. answers A and BE. answers A and C

6. The primary (crank) speed/timing sensor:A. provides engine speed information to the Engine ECMB. provides engine speed information to the Power Train ECMC. is used to calculate shifting points for the Auto KickDown shifting strategyD. all of the above answers (A, B, and C)E. answers A and B

STMG 800 - 205 - Handout No. 5B03/05 Posttest Answers

MACHINE SYSTEMS POSTTEST ANSWERS (continued)Using any of the provided classroom materials, demonstrate your knowledge of the variousmachine systems by circling the BEST ANSWER for each of following questions.

The Hydraulic Demand Fan System

7. The sensors (inputs) used to control the hydraulic demand fan are:A. intake air temperature, coolant temperature, and fan pump discharge pressureB. intake air temperature and fan pump discharge pressureC. coolant temperature and fan pump discharge pressureD. hydraulic oil temperature, intake air temperature, coolant temperature, and fan pump

discharge pressure

8. When controlling the hydraulic demand fan, the Engine ECM:A. sends maximum current to the fan pump control solenoid to produce minimum speedB. sends minimum current to the fan pump control solenoid to produce maximum speedC. sends maximum current to the fan pump control solenoid to produce maximum speedD. sends minimum current to the fan pump control solenoid to produce minimum speedE. answers A and BF. answers C and D

9. The hydraulic demand fan may be shut OFF by:A. disconnecting the fan pump control solenoidB. using the Cat Advisor Configuration screen to turn fan control OFFC. using the Cat ET Configuration screen to turn fan control OFFD. answers B and CE. answers A and CF. none of the above

10. Maximum fan speed (high pressure cutoff) can be attained by:A. disconnecting the fan pump control solenoidB. using the Cat Advisor Configuration screen to turn fan control OFFC. using the Cat ET Configuration screen to turn fan control OFFD. answers A and BE. answers A and CF. none of the above

STMG 800 - 206 - Handout No. 5C03/05 Posttest Answers

MACHINE SYSTEMS POSTTEST ANSWERS (continued)Using any of the provided classroom materials, demonstrate your knowledge of the variousmachine systems by circling the BEST ANSWER for each of following questions.

11. The Torque Converter Inlet Relief Valve:A. limits the maximum oil pressure to the torque converterB. limits the maximum oil pressure in the torque converterC. protects the components in the torque converter when the oil is coldD. answers A and CE. answers B and C

12. The Torque Converter Outlet Relief Valve:A. ensures a constant oil pressure to the torque converterB. maintains a constant maximum oil pressure inside the torque converterC. maintains a constant minimum oil pressure inside the torque converterD. limits the maximum temperature inside the torque converterE. answers C and D

13. The Transmission Main Relief Valve maintains the oil pressure:A. for the operation of the transmissionB. for the operation of the torque converterC. for the operation of the steering clutches and the brakesD. all of the above answersE. answers A and C

14. The steering clutches are:A. spring applied and hydraulically releasedB. hydraulically applied and spring releasedC. hydraulically applied and hydraulically released

15. The brakes are:A. spring applied and hydraulically releasedB. hydraulically applied and spring releasedC. hydraulically applied and hydraulically released

16. When the service brakes are FULLY APPLIED (ENGAGED) using the service brake pedal:A. the proportional brake valve solenoids are DE-ENERGIZED and the secondary brake

valve solenoid is ENERGIZEDB. the proportional brake valve solenoids are ENERGIZED and the secondary brake valve

solenoid is DE-ENERGIZEDC. the proportional brake valve solenoids are DE-ENERGIZED and the secondary brake

valve solenoid is DE-ENERGIZEDD. the proportional brake valve solenoids are ENERGIZED and the secondary brake valve

solenoid is ENERGIZEDE. none of the above answers

STMG 800 - 207 - Handout No. 5D03/05 Posttest Answers

MACHINE SYSTEMS POSTTEST ANSWERS (continued)Using any of the provided classroom materials, demonstrate your knowledge of the implementsystem by entering the letter of the BEST ANSWER for each of the implement systemcomponents listed at the left.

The Implement Hydraulic SystemI Hydraulic oil tank

D Implement pump

K Pressure reducing manifold

G Implement lockout solenoid valve

B Pilot oil filter

A Dozer and ripper control valves

J Lift dump valve

M Tilt dump valve

L Shuttle valve

E Solenoid controlled pilot valve

H Quick-drop valve

F Implement ECM

C Hydraulic oil cooler bypass valve

A. Direct the flow of high pressure pump supply oilto the implement cylinders.

B. Ensures that clean oil is delivered to the solenoidcontrolled pilot valves.

C. Opens to bypass the cooler when the hydraulicoil is cold and closes when the hydraulic oil iswarm to direct oil through the cooler.

D. Provides oil flow through the entire hydraulicsystem for the operation of the implements.

E. ENERGIZED by the Implement ECM to directpilot pressure oil to move an implement controlvalve spool.

F. Receives signals from implement control leversensors and sends corresponding currents to theappropriate solenoid controlled pilot valves.

G. Blocks the flow of pilot pressure oil to the EHpilot manifold when DE-ENERGIZED.

H. Directs rod-end oil from the blade lift cylindersinto the head-ends when the blade falls rapidlyto the ground.

I. Serves as a reservoir for the hydraulic oil.

J. Is closed by high pressure supply oil to shut offoil flow to tank when a blade lift or a ripperfunction is active.

K. Contains the pressure reducing valve and theDead Electric Lower valve.

L. Directs high pressure supply oil to the lift dumpvalve and the lift relief valve when a blade liftfunction is active.

M. Is closed by high pressure supply oil to shut offoil flow to tank when a blade tilt function isactive.

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STMG 800 - 208 - Handout No. 603/05 Posttest Answers

d10t (rjg) service training

Documents

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implementhydraulic system

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