Manual Drivetrain and Axles Flashcards
7 cards from real NAPA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Manual Drivetrain and Axles flashcards as text
A whine from the rear differential is heard on acceleration and goes away when coasting. What is the most likely cause?
Answer: Incorrect ring and pinion contact pattern or worn gears
Gear noise that changes with drive and coast load usually points to ring and pinion wear or a bad tooth contact pattern.
A noise from the rear axle is heard only while turning corners. What is the most likely cause?
Answer: Worn differential side gears or pinion (spider) gears
Differential gears only turn relative to each other when the wheels turn at different speeds, which happens in turns.
When checking a ring and pinion gear tooth contact pattern, the pattern shows up on the toe of the drive side. What is usually needed?
Answer: Move the ring gear away from the pinion to increase backlash
A drive-side toe pattern generally means backlash should be increased by moving the ring gear away from the pinion.
A clutch-type limited-slip differential chatters in tight turns after a fluid change. What is the most likely fix?
Answer: Add the specified friction modifier or limited-slip additive
LSD clutch packs need a friction modifier to engage smoothly, and leaving it out causes chatter.
On a C-clip retained rear axle, what must be removed before the axle shaft can be pulled out?
Answer: The differential cover, pinion shaft lock bolt, and pinion shaft, then the C-clip
The C-clip sits inside the differential, so the pinion shaft must come out before the axle can be pushed in and the clip removed.
A 4WD vehicle with a part-time transfer case binds and hops in tight turns on dry pavement while in 4H. What is the cause?
Answer: Normal driveline windup because there is no center differential
Part-time systems lock the front and rear driveshafts together, so different axle speeds in turns cause windup on high-traction surfaces.
Why is a crush sleeve used on many drive pinion assemblies?
Answer: To set pinion bearing preload
Tightening the pinion nut collapses the crush sleeve until the specified bearing preload (turning torque) is reached.