ASE ASE Manual Drive Train and Axles 1 — Questions and Answers
Question 1: A manual transmission grinds when shifting into 2nd gear but all other gear changes are smooth. What is the MOST likely cause?
- Worn main shaft bearing
- Faulty 2nd gear synchronizer assembly (Correct answer)
- Low transmission fluid level
- Bent shift fork for 3rd/4th gear
Correct answer: Faulty 2nd gear synchronizer assembly
Grinding specific to one gear indicates the synchronizer for that gear is worn and cannot match shaft speeds before engagement.
Question 2: A technician notices a manual transmission is hard to shift into any gear when the engine is running but shifts freely with the engine off. What component is MOST likely at fault?
- Worn shift linkage
- Clutch not fully releasing (dragging clutch) (Correct answer)
- Worn synchronizer rings on all gears
- Loose flywheel bolts
Correct answer: Clutch not fully releasing (dragging clutch)
A dragging clutch does not fully disengage the input shaft from the engine, keeping the gearset spinning and making engagement into any gear difficult.
Question 3: What is the function of the pilot bearing or bushing in a manual transmission system?
- It supports the rear of the crankshaft
- It supports the front of the transmission input shaft in the crankshaft (Correct answer)
- It preloads the input shaft bearing
- It centers the clutch disc on the flywheel
Correct answer: It supports the front of the transmission input shaft in the crankshaft
The pilot bearing or bushing supports the tip of the transmission input shaft inside the crankshaft, keeping it aligned when the clutch is released.
Question 4: A rear-wheel-drive vehicle vibrates at highway speeds but the vibration disappears when the driver lightly applies the brakes. What is the MOST likely cause?
- Out-of-balance tires
- Worn universal joint in the driveshaft (Correct answer)
- Loose transmission crossmember mount
- Faulty wheel bearing
Correct answer: Worn universal joint in the driveshaft
A worn or loose universal joint produces a vibration that changes under load; lightly braking shifts the driveline load, altering the phase angle and temporarily reducing the vibration.
Question 5: What is the purpose of the clutch release bearing (throw-out bearing)?
- It transfers torque from the flywheel to the clutch disc
- It allows the non-rotating clutch fork to apply force to the spinning pressure plate fingers (Correct answer)
- It pre-loads the clutch disc against the flywheel
- It supports the transmission input shaft
Correct answer: It allows the non-rotating clutch fork to apply force to the spinning pressure plate fingers
The release bearing is a thrust bearing that contacts the spinning pressure plate diaphragm spring fingers while the clutch pedal is depressed, allowing stationary fork force to release the rotating assembly.
Question 6: During a clutch replacement, a technician finds the flywheel surface has heat cracks and hard spots. What is the recommended repair?
- Install the new clutch disc on the cracked flywheel — surface irregularities will wear in
- Resurface the flywheel if within specifications or replace it (Correct answer)
- Apply a thin bead of RTV to smooth the surface before assembly
- Reverse the flywheel so the cracked side faces away from the clutch
Correct answer: Resurface the flywheel if within specifications or replace it
Resurfacing removes heat cracks and hard spots if the flywheel is within minimum thickness; otherwise replacement is required to ensure proper clutch engagement and heat dissipation.
ASE ASE Manual Drive Train and Axles 1
A manual transmission grinds when shifting into 2nd gear but all other gear changes are smooth.
What is the MOST likely cause?