ASE G1 Auto Maintenance and Light RepairManual Drive Train and AxlesHard
A vehicle with a manual transmission experiences a sudden loss of drive, but the engine runs normally and the clutch pedal feels correct. When the transmission is shifted into any gear, the shift lever moves freely, but no power is transmitted to the wheels. This condition MOST likely indicates a failure of which component?
- AShift fork
- BClutch disc splines
- CDifferential side gears
- DTransmission main shaft bearing
Show answer & explanationAnswer & explanation
Correct answer: B. Clutch disc splines
A sudden loss of drive with a normal-feeling clutch and engine, but no power transmission in any gear, points to a mechanical disconnect between the clutch disc and the transmission input shaft. This is most commonly caused by stripped clutch disc splines, which would prevent the input shaft from receiving power from the clutch.
Why the other options are wrong
- A. A broken shift fork would prevent engagement of a specific gear or gears, or prevent the lever from moving freely, but wouldn't cause a complete loss of drive in all gears if the lever still moves freely.
- C. Failure of differential side gears would typically result in power being sent to only one wheel (if it's an open differential) or cause severe grinding/clunking, not a complete loss of drive where the transmission seems to engage but no power goes to wheels.
- D. A failed main shaft bearing would cause significant noise, vibration, and potentially difficulty shifting, but not a complete loss of drive where the shift lever moves freely and no power is transmitted.
Stripped Clutch Disc Splines
Damage to the internal splines of the clutch disc, causing it to lose its mechanical connection with the transmission input shaft, resulting in a complete loss of drive.
- Engine runs, clutch pedal feels normal, but no power to wheels.
- Transmission shifts freely, but no drive.
- Requires clutch disc replacement.
Memory trick: Engine runs, gears engage, but no go? Splines let go!