ASE G1 Auto Maintenance and Light RepairManual Drive Train and AxlesHard
A technician is performing a differential backlash measurement. The specification is 0.005-0.008 inches. The technician measures 0.015 inches. What is the MOST appropriate corrective action?
- AAdjust the carrier bearing preload.
- BReplace the differential gears.
- CAdjust the ring gear position using shims.
- DIncrease the pinion depth.
Show answer & explanationAnswer & explanation
Correct answer: C. Adjust the ring gear position using shims.
Excessive backlash indicates too much clearance between the ring and pinion gear teeth. Backlash is primarily adjusted by moving the ring gear closer or further from the pinion gear using shims at the carrier bearings. Increasing pinion depth affects the contact pattern, not primarily backlash.
Why the other options are wrong
- A. Carrier bearing preload ensures proper bearing life and stability, but it is not the primary adjustment for ring and pinion backlash.
- B. Replacing the gears is a last resort if they are excessively worn or damaged, but adjustment should always be attempted first if the issue is only excessive backlash.
- D. Pinion depth adjustment affects the tooth contact pattern, not primarily the backlash. Increasing depth would move the pinion deeper relative to the ring gear, potentially worsening backlash or creating other issues.
Differential Backlash
The amount of clearance or play between the teeth of the ring gear and the pinion gear in a differential, critical for proper gear mesh and quiet operation.
- Measured with a dial indicator.
- Too much backlash causes clunking and noise.
- Adjusted by moving the ring gear laterally with shims.
Memory trick: Backlash is a side-to-side shim slide.