analisis motor de traccion (ingles).pdf

8/10/2019 Analisis Motor de traccion (ingles).pdf

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AA02084

Oil sampling must be done every 250 hours of operation. The sample must be taken within a half an hourof truck shut down and within an hour of actual truck operation. Oil samples that are not taken under thisstipulation will not convey an accurate measurement of wheel motor condition.

When taking an oil sample, it is important to position one of the magnetic plugs in the six oclock posi-tion on the wheel. Oil samples should be taken from this plugged hole using a flexible tube that is 18

inches (457 mm) in length. The tube must be inserted downward exactly 12 inches (305 mm) toward the bottom of the torque tube.

When a sample is extracted from the wheel motor and placed in a clear bottle, the appearance, as well asodor of the oil should be inspected. Note any burning smells or other odors typical of fatigued or contam-inated oil. Check the oil for cloudiness, large particles, and filming. Any of these conditions indicate a

problem.

A gradual rise of elements between oil samples is normal. Only when a sharp increase occurs is there evi-dence that a mechanical failure is imminent. Levels of elements that indicate mechanical stress differfrom element to element. Additionally, oil sampling criteria established for each element may differ at

each mine site due to factors such as uphill or downhill hauling, grades, and speeds.

Elements for the wheel motor that can be detected with oil analysis are iron (Fe), chromium (Cr), nickel(Ni), copper (Cu), silicon (Si), phosphorus (P), zinc (Zn), and calcium (Ca). Monitoring and plotting lev-els of these elements should aid in identifying operational status of the wheel motor. Rapid changes orhigh levels of these elements are indicators that problems exist in the mechanical components.

As stated above, some guidelines for analyzing oil samples can be given, but specific levels should beestablished at the operating mine site. The element type, maximum ppm, maximum spike allowable

between 250 hour interval oil samples, oil sample indicators, and possible causes and actions are listed inthe following charts. These charts provide basic guidelines for analysis of oil sampling information.

Action: A sun pinion and magnetic plug inspection should be done immediately. The magnetic plugsshould be inspected for metal chips and shavings. The sun pinion and low speed planet gears should beinspected for wear or spalling per GE Transportation Systems AC Wheel (GDY85) Transmission GearUse Criteria. If the low speed planet gears fail to meet the inspection criteria the wheel should beremoved, disassembled, and gears replaced. If the low speed planet gears meet the re-use criteria, but thesun pinion fails to meet the reuse criteria, then replace the sun pinion. Once the sun pinion has beenreplaced drain the oil and replace with fresh oil. This wheel should then be monitored closely andreplaced if the iron level spikes again.

Max spike

100

Possible cause of elevated ppm's

Iron (Fe)

If iron levels are high and otherelements are slightly elevated:

"Soft" iron contamination. Sources are likely tobe casting material.200

Element Max ppm Indications of oil samples

600If iron levels are high and otherelements ppm's are rising rapidly:

"Hard" iron contamination. Sources are likelyto be bearing, gears, etc.

ELEMENT SPECIFICATION CHARTS


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Action: The oil should be resampled immediately and a gear train inspection completed. If the resampling of the oil shows high chrome, the wheel should be removed from service, disassembled, and the bearings and gears inspected.

Action: This could indicate a condition such as gear tooth pitting or spalling. The oil should be resampledimmediately and a gear train inspection completed. If the resampling of the oil shows high nickel andchromium, the wheel should be removed from service, disassembled, and the bearings and gearsinspected.

Action: This often indicates a normal wear condition such as minor thrust washer wear. It can also be anindicator of bearing wear. If bearing wear is a concern review the chromium readings in conjunction withthe copper readings. If both the copper and chromium readings spike; remove the wheel from service,disassemble the wheel, and inspect the bearings. If the only elevated reading is that of copper or lead;remove the sun pinion and check the outer thrust washer for wear. If the outer thrust washer has worn lessthan the depth of the oil lubricating grooves then reassemble the sun pinion, filter the oil and continue tomonitor. If the outer thrust washers have worn more than the depth of the oil lubricating grooves thenreplace the outer thrust washers, reassemble the sun pinion, filter the oil and continue to monitor.

Action: If calcium and zinc spike then look at the oil viscosity. If the oil viscosity is below the 53 cSt at100 C (212 F) or 588 cSt at 40 C (104 F) condemning limit, the oil should be resampled immediately.If the resampling still shows a spike in calcium and low viscosity remove the wheel, disassemble, andreplace the internal brake seals. The oil removed from a low viscosity wheel should be disposed of andnot reused under any circumstances. If the oil viscosity is above 53 cSt at 100 C (212 F) or 588 cSt at40 C (104 F) then monitor the wheel for any further changes in viscosity

Action: If zinc and calcium increase proportionally then look at the oil viscosity. If the oil viscosity is below the 53 cSt at 100 C (212 F) or 588 cSt at 40 C (104 F) condemning limit, the oil should be resa-mpled immediately. If the resampling still shows a spike in calcium and low viscosity remove the wheel,disassemble, and replace the internal brake seals. The oil removed from a low viscosity wheel should be

Max spike

7

Possible cause of elevated ppm's

10Chromium

(Cr)

Element Max ppm Indications of oil samplesIf chromium is high and iron is high: A bearing failure is likely in progress.

Max spike

5

Possible cause of elevated ppm'sElement Max ppm Indications of oil samples

Nickel (Ni) 10 If nickel is high and iron is high or rising: Nickel is likely from one or more of the gears.

Max spike

15

Possible cause of elevated ppm'sHigh iron will produce high copper from the thrust

washers and bearings.

Element Max ppm Indications of oil samplesIf copper is high with iron high:

If copper is high with other elementslow:

Copper (Cu) 5020

A thrust washer is rapidly wearing with the likely causeof the sun pinion gear thrusting inboard or outboard.

Max spike Possible cause of elevated ppm'sElement Max ppm Indications of oil samples

Calcium (Ca) 40If calcium, zinc, and phosphorus arehigh:

Hydraulic oil has entered the drive train.20

Max spike Possible cause of elevated ppm'sIndications of oil samplesMax ppmElement

High mechanical wear of components isoccurring.

75Zinc (Zn)

If zinc is high without high calcium andphosphorus:

If zinc, phosphorus, and calcium are high: Hydraulic oil has entered the drive train.40

25


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As stated earli er , replacement of the sun pin ion gear i s scheduled every 3,500 hours (standard gearratio) or 10,000 hour s (low gear r atio), but contamination can reduce sun pinion gear l if e signif i- cantly, as well as the rest of th e dri ve train . Al though the inspection i nterval for th e sun pin ion gear

in spection is every 500 operational hour s, additional in spections may be requi red if oil samples from awheel motor show elements are above nor mal or rapidl y elevatin g.

Particle Size Analysis

When filtering synthetic oil for reuse, the oil must be monitored to determine when filtering is necessary.The process of monitoring the oil for this purpose is particle size analysis. The test consists of passing a

beam of light through the oil as it passes through a clear tube. A computer analyzes the quantity and sizeof particles contained in the oil.

Particles that are smaller than 5 microns in size are not large enough to cause any gear or bearing failures.Particles over 25 microns can damage bearings and must be filtered from the oil.

General Electric (GE) recommends that the oil be tested according to the International Standards Organi-zation's ISO Particle Analysis 4406. This standard documents the size and number of particles permittedin the lubricant. This is an extremely important measurement of the condition of the oil.

An "ISO Cleanliness Code" is used to document the number and size of the contaminates that can be tol-erated in a specific application of a lubricant. An example of an "ISO Cleanliness Code" would be 18/13.The first number (18 in this example) applies to the allowable number of particles between 5 - 15 micronsin size. The second number (13 in this example) applies to the allowable number of particles between 15- 25 microns. If the particle count identified by the "ISO Cleanliness Code" is exceeded or there are parti-cles present larger than 25 microns, the oil should be filtered.

GE recommends that a Cleanliness Code of 18/13 be used for motorized wheels. Oil qualified for reusemust be filtered to 10 microns absolute.

If particle analysis yields a result of greater than 18 for the top number or greater than 13 for the lowernumber the motorized wheel oil should be filtered to 10 microns absolute. On occasion, one should checkthe results of the filtering process to assure the filtering process is yielding the desired results. Should theresult be unacceptable check the filter type, particle size, and condition prior to refiltering.

Oil Viscosity

Viscosity of filtered oil must be monitored by oil analysis to ensure proper lubrication. Viscosities belowthe condemning limit indicates entry of contamination that will affect the oil film and lubricating quality.The condemning limit for 680 oil, is 53cSt when tested at 212 F (100 C), and 588cSt at 104 F (40 C).This value can be used along with element tracking of phosphorus, calcium, and zinc to verify correct oilviscosity. Ensure the appropriate viscosity value is being maintained for the approved oil you are using. Ifthe viscosity of the oil is below the acceptable limit, the oil should be rechecked. If the second test fails,


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dispose of the oil. Fill the wheel motor with new, GE approved oil. The contaminated oil should be prop-erly disposed of according to local regulations.

I f the viscosity of the oil i s below condemni ng l imi ts, the oil may be contaminated with hydraul ic oil .

Ensure all join ts are properl y sealed before fil li ng the wheel motor with fr esh oi l. I f hydrauli c oil con- tinu es to contaminate the wheel motor , ser ious damage to in ternal components may resul t.

Refer to Parts and Service News Bulletin, AA02083, "APPROVED SYNTHETIC OILS AND GUIDE-LINES FOR USE IN GDY85 WHEEL MOTORS" for additional information on synthetic oil guidelines.

Magnetic Plug Inspection. (See Appendix A for Photographic Examples).

During the 500 hour sun gear inspection, all of the magnetic plugs must be removed and inspected. Thereare 8 magnetic pipe plugs (part GE0086) on the outboard side of the wheel in a circular pattern near thecenter of the wheel motor. Refer to Figure 1. The purpose of the magnetic plugs is to gather any ferrousmetal from the oil and prevent the material from circulating through the moving components. The normalappearance of the magnetic material should be coated with a light film of oil and fine metal particles. Thiswould indicate normal operation of the wheel motor.

FIGURE 1.

Magnetic plug location on outside of wheel motor housing. There are 8 plugs on each wheel motor.


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If there is a heavy build up of metal or large visual particles on the magnetic plugs, a source of metal con-tamination exists in the wheel motor. Refer to Figure 3. The wheel motor must be flushed or replaced if

previously flushed. The flushing fluid used must be the same oil used in the wheel motor during normaloperation. Solvents or light weight oils must not be used due to the risk of contamination.

FIGURE 2.

A brand new plug (GE0086).

FIGURE 3.

Magnetic plug with excess of ferrous material. Thewheel motor must be replaced.


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If any of the plugs are missing the magnetic inserts, the wheel motor must be flushed. Refer to Figure 4.Occasionally magnetic inserts can dislodge and circulate through the drive train. Plugs missing magneticinserts must be replaced with a new plug (GE0086) before installing into the wheel motor.

Light oil and fine particle coating on the plugs is normal. Refer to Figure 5. Clean the debris from the plugs prior to reinstalling. Contamination by nonferrous metals (copper, calcium, etc.) should beobserved in the oil sample history of the wheel motor.

FIGURE 4.

Plug with its magnetic insert missing. Discard andreplace with a new plug before installation.

FIGURE 5.

This plug shows normal buildup of ferrous materialindicating good mechanical performance of wheel motor.


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Sun Gear Removal

Ensure that the truck wheels are properly chocked and secured according to local safety practices and procedures. Remove the sun gear per Parts and Service News, " 930E WHEEL MOTOR SUN PINIONGEAR" (AA01052a). This bulletin outlines fabrication of special tooling for sun gear removal, as well asremoval and installation procedures.Inspection of the sun pinion gear and thrust washers can be done after removal from the wheel motor. Oil

and other material must be cleaned from the components so that a visual inspection can be performed.

Thrust Washer Inspection

After removing the thrust washers from access cover (shown in Figure 6), clean with solvent or cleanerand visually inspect the 3 thrust washers. Refer to Figure 6 thru Figure 12 for various pictures of thrustwasher conditions.

The steel thrust washers are heat treated to produce a hardened surface and very little wear is expected.There may be slight discoloration from heat on the surface of the steel but no material should be removedor missing during wheel operation. The steel surfaces must be smooth and free of any dents, scratches, orsevere discoloration.

FIGURE 6.

Thrust washer stack in recess of cover. The stack of thrust washers is always installed with the bronzewasher in between the two steel washers.


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The bronze thrust washer has radial oil grooves to aid in oil transfer. Bronze washers should be orange/ brown in color with wear marks on the contact surfaces from the steel thrust washers.

The two steel thrust washers and the bronze thrust washer are the same thickness. The outside and insidediameters do not need to be checked. The thickness of the thrust washers must be 0.230 to 0.250 inches(5.84 to 6.35 mm). If the thickness of either the bronze or steel washers does not meet specification,replace the washers. Currently, the steel washer part number is GE0076 and the bronze washer part

number is GE0077.

If there has been contamination in the drive train of the wheel, both the bronze and steel thrust washerswill show damaged surfaces. If soft iron was the contaminant, the contact surfaces of the thrust washerswill have a glazed look. If the thrust washers are still within dimensional tolerances, it is possible to reuse

both steel and bronze washers. The wheel motor must be flushed if oil samples show the presence of softiron contamination and no other high level of elements. Continued monitoring of oil samples for indica-tions of soft iron contamination. Replace the wheel motor if problems persist.

Grooves in the steel thrust washers that can be seen and felt are the result of hard iron particles in the oil.The bronze thrust washer will show similar grooves and will likely be worn below dimensional toler-ances. Particles may be imbedded in the bronze thrust washer making replacement necessary. Refer toFigure 12. The oil samples of a wheel motor with severely worn thrust washers should show high levelsof all elements. If the oil samples confirm high element levels, the wheel motor must be replaced.

Oil samples showing high levels of copper (Cu) without high levels of other elements indicates the possi- bility of the sun pinion gear thrusting either inboard or outboard under heavy load. This heavy load willresult in rapid wear of the bronze thrust washer on the inboard or outboard side. The inboard bronzethrust washer in not accessible from the sun pinion gear access cover. Only oil samples will indicateexcessive wear on the inboard thrust washer. Excessive wear on the inboard bronze thrust washerrequires wheel motor replacement.

Excessive wear on the outboard bronze thrust washer due to sun gear thrusting can be addressed by sungear replacement and thrust washer replacement. If continued sun gear thrusting occurs, replace thewheel motor.

FIGURE 7.

Typical thrust washer set after 5,000 hours of operation. There is slight heat coloring on thesteel thrust washers, and slight wear on the bronze washer. Thrust washers in similar conditionare acceptable for reuse if thickness is within specifications.


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FIGURE 8.

Thrust washer set damaged by contamination. The two steel washers are on theleft and the bronze on the right. Replace thrust washers in similar condition.

FIGURE 9.

Steel washer worn and discolored from high stress loads. This washer must be replaced.


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FIGURE 10.

Bronze washer worn and discolored from high stress loads.This washer must be replaced.

FIGURE 11.

Bronze washer discolored by heated oil congealing. Washers inthis condition must be replaced.


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Sun Pinion Gear Inspection

Sun pinion gear inspection should proceed only after cleaning the gear. Only a visual inspection isrequired. There are several observations that should be noted while examining the gear. The following

paragraphs outline several conditions to look for during the inspection. Refer to Figure 13 thru Figure 26for various examples of sun gear failures.

Sun gear tooth surface condition reveals the condition of the sun pinion gear. If manufacturing machiningmarks can be seen on the tooth surface from the tooth tip to the root, the sun gear is likely still good. Ifmachining marks are not visible and the tooth surface is a dull gray, the face of the tooth has worn.

Tooth wear does not necessarily require sun pinion gear replacement. Closer examination of oil sample

history and gear history is needed to determine sun gear life expectancy.

Spalling (material loss) on tooth surfaces is the most obvious sign of sun pinion gear fatigue. Replace-ment of the wheel motor or sun pinion gear depends on the amount of spalling and the time period spal-ling has occurred. A visual inspection will show the amount of spalling and oil sample history will showapproximate hours of operation with contamination. Particles spalling from the sun pinion gear are "hard"

particles. "Hard" particles, if extensive and not detected in time, can cause severe damage to other wheelmotor components.

FIGURE 12.

Bronze thrust washer with imbedded metal particles. Thrust washers in this condition must be replaced. The wheel motor must be replaced, as well, due to contamination.


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FIGURE 13.

Sun pinion gear with inboard spalling near spline.Sun gears such as this must be replaced.


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Spalling can occur on the inboard portion of the sun gear tooth near the high speed carrier spline section.This type of spalling tends to occur after there is noticeable wear from the top to the root of a tooth. Highwear or a "step" formed at the low speed planet gear contact area would require replacement of the sun

pinion gear. If there are excess levels of elements, the wheel motor must be flushed. Significant spalledmaterial will require wheel motor replacement. Oil sample history should show the extent of spalling.

The early stages of spalling can also start as a pitting line below the gear tooth center in the middle of the

gear. The pitting line can be difficult to see and may require a magnifying lens to fully observe this line.Refer to Figure 20. The pitting line will typically run down the length of the gear. As time progresses, a

pit will begin breaking material away towards the top of the tooth. If a large section of gear tooth has bro-ken away, the wheel motor must be replaced because of damage to other components. If only the pittingline is visible, flush the wheel motor and replace the sun pinion gear. Continue monitoring oil samples forindication of additional damage.

Thrusting of the sun gear can occur in some wheel motors. Thrusting of the sun pinion gear toward theoutboard side of the wheel is obvious on the sun gear and the thrust washers. In the early stages of out-

board thrusting, the sun pinion gear and thrust washers should be replaced. Continue oil sample monitor-ing for gear thrusting and replace wheel motor if thrusting persists. Severe thrusting with excess damage

to the sun gear and thrust washer will require wheel motor replacement.

Evidence of inboard thrusting of the sun gear only appears in oil samples analysis. There is little or noindication on the sun pinion gear of inboard thrusting. If oil samples show high copper (from sun piniongear thrusting the inboard thrust washer), replace the sun pinion gear. If high copper levels still exist afterreplacement of the sun pinion gear, the wheel motor must be removed and disassembled to determine thecause of the problem.

If "dents" are observed on the tooth surface this indicates "hard" iron particles are present in the wheelmotor. If the source of the hard particles is not the sun pinion gear, another gear or bearing is likely con-taminating the oil. Flushing may remove the contamination temporarily, but the source will continue con-

taminating the system. Oil samples will show the extent of contamination and indicate wheel motorremoval and replacement is likely required.

Tooth surfaces may have marks on the surface but have not penetrated the hardened surface of the tooth.These marks or "shadows" are from "soft" material such as bronze or cast material. The gear is still reus-able, but flushing the wheel motor is necessary. Future oil samples must be monitored for continuouscontamination and may require wheel motor replacement.

Carefully examine the tooth tips of the sun pinion gear. If contact with the low speed planet gears is at thetooth tip, damage is minimal, and oil sample history is acceptable, replacing the sun gear and flushing thewheel motor should be sufficient. If significant material is lost from the tooth tips, and oil sample historyshows high levels of elements, the wheel motor must be replaced.

Examine the root between each gear tooth for cracks. Cracks will start at either the inboard or outboardside of the gear, and left undetected, will typically extend the full length of the gear. Early stages ofcracking may contribute only minor particles to the oil samples. Flushing and sun gear replacementshould resolve this issue.


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AA02084

FIGURE 14.

Sun pinion gear with spalling from lower contact surface towardsthe tip of the tooth.

FIGURE 15.

Close inspection reveals pitting line located near root of the tooth andextending the entire length of the gear. The sun gear must be replaced.


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FIGURE 16.

Sun pinion gear with severe outboard thrusting andlight spalling beginning in root of tooth. This gear must be replaced.

FIGURE 17. FIGURE 18.

Damaged outboard collar of sun pinion gear due to thrusting.

Light spalling starting on lower portion of gear tooth.


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FIGURE 19.

View of gear tooth with naked eye does not show pitting. See picture below.

FIGURE 20.

The same gear as above. The pitting shown is near the root of thetooth and is not visible to the naked eye. The pitting will beginspalling in about 500 to 1000 operating hours. This gear must bereplaced.


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AA02084

FIGURE 21.

Sun gear with tooth tip contact and additional "dents"from debris. A close up of the gear is pictured below.

FIGURE 22.

This gear has severe tooth tip contact and must be replaced. In addition, numerous dents also require gearreplacement.


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AA02084

FIGURE 23.

FIGURE 24.

Debris damage from "hard" particles near or on the tooth tip. Thelikely source of the debris is a bearing or another gear. If the impactsare minor and widely spaced, a pencil grinder can be used to removesharp edges and reuse the gear.


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FIGURE 25.

FIGURE 26.

Cracking of sun pinion gear through the tooth root. Cracks typically begin at the end of the gear and progressively extend the entire length. Gear replacement at the early stages of cracking is critical.


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AA02084

Low Speed Planet Gear and Bearing Inspection

Prior to reinstalling the sun pinion gear, the low speed carrier planet gears and bearings must be exam-

ined. Only a portion of the low speed planet gears and bearings can be seen through the sun pinion gearaccess hole. More of the bearing is visible through the magnetic plug holes. To help look at visible rollersand races of the bearings, it is recommended to use a pocket type inspection mirror. This will aid theobservation in the cramped area of the bearings. If oil samples and/or sun pinion gear show signs of"hard" iron, a low speed planet gear or bearing may be the source. Refer to Figure 27 thru Figure 31 forvarious pictures of planet gear and bearing failures.

If low speed planet gears or bearings are suspected of contaminating oil, additional effort may be requiredto identify this problem. If the side of the truck is raised off the ground, the tire can be rotated to betterexamine low speed planet gears and bearings.

Using the same criteria as the sun pinion gear, examine low speed planet gears. Though bearing races androllers are only partially visible, it is still necessary to examine for material spalling on both. If earlystages of gear or bearing failures are discovered, it is possible to remove the low speed carrier assemblyfrom the truck without removing the wheel. (Special tool AK4782 is available to support the carrier dur-ing the removal and installation.) If required, remove the low speed carrier assembly and install a replace-ment. Send the removed carrier assembly to an approved rebuild facility for repair.

If spalling of low speed planet gear or bearings is advanced and oil samples show high element levels,replace the wheel motor.

FIGURE 27.

Bearings are press fit into the low speed planet gears.


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FIGURE 28.

When examining planet gear bearings, look for spalling on all parts of the bearings suchas the rollers and the visible section of the bearings races. If spalling is evident, replace thewheel motor.

FIGURE 29.

Inboard side of low speed planet gear with spalling in the tooth center. The wheel motorshould be replaced if this condition is observed.


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FIGURE 30.

Low speed planet gear with impact damage at the tooth tip. The wheel motor must be replaced.

FIGURE 31.

Low speed planet gear with tooth corner chipped. The wheel motor must be replaced.


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INSTALLING COVER PLATE

NOTE: Examine the condition of the shims. If any shims are damaged, replace the shims with new shimsof the same thickness. Do not change the thickness of the shim pack.

Install the shims and the cover plate to the low speed carrier after inspections and repairs are complete. A

small amount of silicon rubber adhesive must be used during installation to seal the cover. Tighten thecover plate capscrews to a torque of 58 2 ft.lbs. (79 3 Nm).

WHEEL MOTOR OIL LEVEL CHECK

With all components reinstalled, inspection report completed, and a copy of the oil sample history filedwith the inspection report, the truck is ready to release until the next oil sample analysis and sun pinioninspection intervals.

FIGURE 33.

When checking the oil level, the wheel should be rotated until a magnetic plug is in the6 oclock position at the bottom of the wheel. The oil level should reach the bottom of this

opening as illustrated above.

Proper oil level


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