Differential Assembly and Axle Maintenance

What is the purpose of pinion depth in a differential assembly?

What can cause wear to the pinion gear thrust washers?

How can correct drive pinion depth be determined?

What is the purpose of preloading side bearings in a differential assembly?

How is backlash corrected in a differential assembly?

Which lubricant is commonly used in most differentials?

What is the purpose of an additive in a limited-slip differential?

What is the purpose of the tooth contact pattern test in a differential assembly?

What are the methods used to support the final drive pinion shaft in a differential assembly?

What is included in differential assembly identification?

What does a grinding or growling noise while turning indicate in a differential assembly?

The drive pinion gear of the drive axle is driven by a companion flange.
Two methods are used to support the final drive pinion shaft: overhung and straddle-mounted.
Pinion depth helps adjust the gear tooth relationship between the ring and pinion gears.
Side bearings are pressed onto the differential case and preloaded to ensure rotation without movement.
Axle specifications must be determined before any service work is performed.
Differential assembly identification includes visual identification, axle assembly number, limited-slip identification tag, and differential cover shape.
The axle ratio of a differential can be determined without removing the housing cover.
Excessive tire spinning or different tire sizes can cause wear to the pinion gear thrust washers.
Grinding or growling noise while turning indicates a defective axle bearing.
Whine noise during cruise indicates drive pinion bearings are the likely cause.

Visual and noise analysis tests are used to check for axle assembly problems.
Tooth contact pattern test checks for proper drive pinion depth and backlash.
Tapered roller bearings require proper preload for support and positioning of pinion shaft.
Preload shims or collapsible spacer are used to ensure proper drive pinion gear preload.
Correct drive pinion depth can be determined through wear pattern analysis, markings on the drive pinion, or gauging set and depth micrometer.
Backlash is the clearance between the drive pinion gear and ring gear and should not vary over 0.002 inch.
Backlash is corrected by transferring shims or turning threaded adjusters.
Thicker shims are placed between housing and differential to provide for proper preload on side bearings.
Gear lubes are specified by API and most differentials require SAE 80W-90 GL-5, SAE 75W-90 GL-5, or SAE 80W GL-5.
Limited-slip differentials use an additive to modify friction characteristics of rear axle lubricant.

Test your knowledge on drive axles and differentials with this informative quiz! From gear tooth relationships to axle assembly identification, this quiz covers it all. Sharpen your visual and noise analysis skills to identify common axle problems, and learn about the importance of proper preload on tapered roller bearings. Discover the correct methods for adjusting backlash and drive pinion depth, as well as the gear lubes specified by API. Don't forget to brush up on limited-slip differentials and their unique requirements. Take this