ASE G1 Auto Maintenance and Light RepairManual Drive Train and AxlesMedium
A technician is performing a road test on a vehicle with a manual transmission. They notice that the vehicle shudders or vibrates violently when attempting to accelerate from a stop, particularly when the engine is cold. Once moving, the vibration usually subsides. Which of the following is the MOST likely cause?
- ALoose driveshaft bolts
- BContaminated clutch disc
- CWorn engine mounts
- DWarped flywheel or pressure plate
Show answer & explanationAnswer & explanation
Correct answer: D. Warped flywheel or pressure plate
A shudder or violent vibration specifically during clutch engagement (accelerating from a stop) is a classic symptom of clutch chatter. This is often caused by an uneven friction surface on the flywheel or pressure plate, or sometimes a worn clutch disc.
Why the other options are wrong
- A. Loose driveshaft bolts would cause a clunking or vibration that is more constant with vehicle speed or during acceleration/deceleration, not just during clutch engagement.
- B. A contaminated clutch disc would primarily cause slippage, not a violent shudder, although severe contamination could contribute to chatter.
- C. Worn engine mounts would cause engine movement or clunking, but typically not a violent shudder specifically during clutch engagement.
Clutch Chatter
A condition characterized by a shuddering or violent vibration when engaging the clutch, often caused by uneven friction surfaces, worn clutch components, or misaligned parts.
- Occurs during clutch engagement (accelerating from a stop).
- Can be caused by warped flywheel/pressure plate, oil contamination, or worn disc.
- Often worse when cold or under heavy load.
Memory trick: Shudder from a start? Clutch surfaces fall apart!