ASE G1 Auto Maintenance and Light RepairManual Drive Train and AxlesMedium
A vehicle with a manual transmission exhibits a rumbling noise that is present only when the clutch pedal is depressed. The noise goes away when the pedal is released. Which of the following components is MOST likely causing this noise?
- AInput shaft bearing
- BRelease bearing
- CPressure plate
- DPilot bearing
Show answer & explanationAnswer & explanation
Correct answer: B. Release bearing
The release bearing (also known as the throw-out bearing) is the only component in the clutch system that is actively spinning and under load ONLY when the clutch pedal is depressed. A rumbling noise under this specific condition is a classic symptom of a worn release bearing.
Why the other options are wrong
- A. An input shaft bearing would typically make noise when the transmission is in gear and the clutch is engaged (pedal released).
- C. The pressure plate is a static component when the clutch is depressed; its springs are compressed. Noise from it would typically be a chatter or squeal upon engagement/disengagement, not a rumbling only when depressed.
- D. The pilot bearing supports the input shaft and is under load when the clutch is engaged (pedal released). If seized, it might cause noise when disengaged, but not typically a rumbling only when depressed.
Release Bearing Noise
A distinctive rumbling, growling, or squealing noise heard only when the clutch pedal is depressed, indicating wear or damage to the clutch release (throw-out) bearing.
- Occurs when clutch pedal is depressed.
- Goes away when clutch pedal is released.
- Caused by worn internal bearings in the release bearing.
Memory trick: Pedal down, noise around? Release bearing's going down!