Clutch: Testing and Inspection
Manual Transmission and Clutch
Symptom Chart - Clutch Operation
Inspect Gearshift Mechanism
1. Inspect the gearshift mechanism for:
- signs of damage.
- missing or loose fasteners.
- binding.
2. Repair any concerns as necessary.
Evaluate Transmission
1. Road test the vehicle. Use the following methods to diagnose the concern.
- Start the engine.
- Evaluate the noise in NEUTRAL while vehicle is parked.
- Check whether the noise is present with the clutch fully disengaged (clutch pedal applied). Check to see if the pedal pulsates abnormally (clutch diaphragm finger runout).
- Check whether the noise is present with the gearshift in the NEUTRAL position and the clutch fully engaged (clutch pedal released). Apply the park brake and move the gearshift towards the 1st gear position. Apply very slight pressure and note if the gear noise level is reduced (gear rollover noise).
- With the clutch fully engaged (clutch pedal released) check whether the noise is present as the engine speed is raised. If the noise reduces, note the engine speed at which this occurs.
- Listen for any change in noise while depressing and releasing the clutch pedal.
- Listen for any change in noise while changing the engine rpm.
- Drive the vehicle and shift through all the gears including REVERSE. Listen for any changes in noise.
- Drive the vehicle in the gear in which the noise is most noticeable. Apply the clutch pedal and leave the gear engaged. Listen for any change in noise.
- Drive the vehicle in the gear in which the noise is most noticeable. Apply the clutch pedal and shift the transmission into NEUTRAL. Release the clutch pedal and allow the vehicle to coast.
- Compare the noise to another vehicle. Make sure the transmissions are the same.
2. Compare the road test results with the following symptom charts. The following list of conditions are typical transmission concerns:
GO to Symptom Chart - Transmission Operation Symptom Chart - Transmission Operation or GO to Symptom Chart - NVH Symptom Chart - NVH.