GM Service Manual Online
For 1990-2009 cars only

Diagnostic Information for Front Wheel Drive Transaxle/Transmission Final Drive and/or Front Hub Bearing Hum and/or Grind Noise

Subject:Diagnostic Information for Front Wheel Drive Transaxle/Transmission Final Drive and/or Front Hub Bearing Hum and/or Grind Noise

Models:2000-2006 Passenger Cars and Light Duty Trucks
with Transverse Front Wheel Drive or All Wheel Drive Transaxle/Transmissions



Warranty data and the inspection of final drive units returned to the Warranty Parts Center (WPC) indicate that final drive units are being incorrectly diagnosed and replaced for what is thought to be a final drive unit noise.

    • Warranty data indicates that after a final drive unit is replaced for a noise condition, an additional warranty claim/repair is submitted after the final drive unit has been installed.
    •  Parts returned to the WPC and installed and tested in vehicles are found not to have an objectionable noise level.

Prior to replacing the final drive unit for a noise condition, the technician should install and road test the vehicle with chassis ears or the equivalent.

Tip
These steps are designed to help the technician diagnose the noise concern/condition and are not exclusive to any one cause.

  1. Inspect the tires for abnormal and/or excessive wear. Refer to Tire and Wheel Inspection. An excessively worn or aggressive tire pattern can create an objectionable noise.
  2. Install chassis ears to both front knuckles, the final drive, the engine and transaxle and the engine mounts.
  3. Road test the vehicle on a smooth road surface.
  4. • Typically, a final drive noise will not change with steering wheel input right or left.
    • Typically, if the noise increases and/or changes with steering wheel input to the right, then listen to the left front knuckle/hub area with the chassis ears.
    • Typically, if the noise increases and/or changes with steering wheel input to the left, then listen to the right front knuckle/hub area with the chassis ears.

For additional information, refer to the appropriate SI Document. Again, these steps are designed to help the technician diagnose the noise concern/condition and are not exclusive to any one cause. Use the SI titles below for key word searches.

    • Search Bulletins and PIs
    • Noise and Vibration Analysis
    • Whine Noise Varying with RPM or Fluid Pressure
    • Final Drive Noise or Hum Noise
    • Noise in Random Ranges
    • Whine/Growl Noise That Changes with Vehicle Speed
    • Noise in First, Second, Third, or Fourth
    • Lower Engine Noise, Regardless of Engine Speed
    • Engine Noise Under Load
    • Whine or Growl Noise from Power Steering System
    • Exhaust Noise
    • Noise Diagnosis - Front Suspension
    • Noise Diagnosis - Rear Suspension
    • Constant Noise (with AWD)
    • Intermittent Noise (with AWD)