ASE ASE Manual Drive Train and Axles 2

Question 1

A rear-axle differential makes a howling noise that changes pitch with vehicle speed but not with engine speed. What is the MOST likely cause?

Accepted Answer

Improper ring and pinion gear backlash or worn gear teeth

Answer

Worn pinion shaft bearings with incorrect preload

Answer

Loose ring gear bolts

Answer

Low differential fluid level only

Question 2

When setting up a ring and pinion gear set in a rear axle, what does the gear tooth contact pattern indicate?

Accepted Answer

The correct pinion depth and backlash adjustment

Answer

The amount of gear backlash present

Answer

The ring gear runout

Answer

The differential case bearing preload

Question 3

A 4WD vehicle with an open differential on the rear axle gets stuck with one wheel spinning freely. What limited-slip or locking device would MOST effectively prevent this?

Accepted Answer

Positraction or limited-slip differential

Answer

A larger ring and pinion ratio

Answer

A heavier axle housing

Answer

A stiffer anti-roll bar

Question 4

What fluid is typically required in a limited-slip differential, and why?

Accepted Answer

Gear oil with a limited-slip friction modifier additive to prevent chatter

Answer

Standard gear oil only, because the clutch packs need no lubrication

Answer

Automatic transmission fluid for all limited-slip units

Answer

Engine oil because it has the correct viscosity

Question 5

A technician measures excessive axle shaft endplay on a semi-floating rear axle. What is the MOST likely cause?

Accepted Answer

Worn axle bearing

Answer

Loose axle flange bolts

Answer

Worn or missing C-clip retainer

Answer

Incorrect differential fluid viscosity

Question 6

What is the CORRECT method to check differential bearing preload?

Accepted Answer

Measure the torque required to rotate the pinion with a inch-pound torque wrench

Answer

Check the backlash only — preload is set automatically

Answer

Measure pinion depth with a dial indicator

Answer

Inspect the gear contact pattern only