lesson 9: the drivetrain
DESCRIPTION
Jeff Crawford (Crawfords Auto Repair) explains how the drivetrain works and the parts that it is composed of. Descriptions of the transmission, drive shaft, differential, and transaxle are included. The lesson also explains the differences between a front-wheel drive, rear-wheel drive and four-wheel drive vehicles.TRANSCRIPT
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Free Auto Repair Classes.Lesson 9: The Drive Train
Jeff CrawfordCrawford’s Auto Repair
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The Drive Train
The Drive Train is also called the Power Train
Parts include:◦ Transmission
◦ Drive Shaft (or drive line)
(in 4-wheel or rear-wheel drive vehicle, described later)
◦ Differential
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Recall Chapter 5
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Input from Engine to Transmission
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Transmission Gears and Output
A transmission has gears (like a bicycle) which provide different output ratios.
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Output Ratios
The ratio is the input of the crankshaft to the output of the transmission
1st Gear might have a 4:1 ratio ◦ (4,000 RPM input would have 1,000 RPM output)
2nd Gear might have a 3:1 ratio 3rd Gear might have a 2:1 ratio 4th Gear might have a 1:1 ratio
◦ Aka direct drive, there is no gear reduction
Overdrive, 0.75:1 ratio (better gas mileage)
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Transmissions have gears
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Automatic vs Manual
Automatic Transmission has “sun and planet” gears
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Manual Transmission
Manual or Standard Transmission has conventional gears that are always turning when engine is running and clutch is released
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Driveshaft
Driveshaft connects transmission to rear differential
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Differentials
Differentials have gears◦ Transmit the direction of power 90 degrees (from driveshaft to axle)
◦ Allow an outside tire to turn faster than an inside tire during a turn
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Front-wheel drive vsRear-wheel drive vs4-wheel drive
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Front Wheel Drive
Transmission and differential combined into one piece called a transaxle
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Notice the transfer case and 2 drive shafts in top image.
Which do you expect is a truck vs a sedan with 4-wheel drive for the snow?
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Questions?
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Download the ebook free
http://crawfordsautoservice.com/crawfords-auto-repair-guide-free-ebook/
Also available for print-on-demand and Kindle
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