GM Service Manual Online
For 1990-2009 cars only

A noise or vibration that is noticeable when the vehicle is in motion MAY NOT be the result of the transaxle.

If the noise or vibration is noticeable in PARK (P) and NEUTRAL (N) with the engine at idle, but is less noticeable as the RPM increases, the cause may be from poor engine performance.

    • Inspect the tires for the following:
       - Uneven wear
       - Imbalance
       - Mixed sizes
       - Mixed radial and bias ply -- Refer to Alignment, Wheels, and Tires section in the Chassis Service Manual.
    • Inspect the suspension components for the following:
       - Alignment and wear
       - Loose fasteners -- Refer to Front Suspension section in the Chassis Service Manual.
    • Inspect the engine and transaxle mounts for damage and/or loose bolts.
    • Inspect the transaxle case mounting holes for the following:
       - Missing bolts, nuts, and studs
       - Stripped threads
       - Cracks
    • Inspect the flexplate for the following:
       - Missing or loose bolts
       - Cracks
       - Imbalance

The following chart describes specific noise and vibration concerns relating to the automatic transaxle. The first column describes the symptom, the second column gives the possible causes, and the third column gives the correction for the problem. The call-out numbers in the chart refer to the illustration call-outs in the Major Components section of this service manual.

Complaint/Condition

Possible Cause(s)

Correction(s)

Vibration

Torque converter out of balance

Replace the torque converter.

Missing or loose torque converter bolts/lugs

Tighten/replace the faulty components.

Internal failure of the torque converter

Replace the torque converter.

Output or stub shafts out of balance

Replace the shaft as needed.

Output or stub shaft bushings worn

Replace the bushings as needed.

Turbine shaft out of balance

Replace the bushings as needed.

Turbine shaft bushings worn

Replace the bushings as needed.

RPM sensitive whine, in all ranges, which may be sensitive to RPM load, or which ceases when the TCC engages.

Torque converter faulty

Verify that the noise is internal to the torque converter by placing your left foot on the brake with the gear selector in Drive. Momentarily stall the engine. If the noise increases under load, replace the torque converter.

High pitch whine (in all ranges) which will intensify with engine RPM or which is sensitive to the oil pressure.

Oil pump faulty

Verify that the noise is internal to the oil pump during a preliminary oil pressure check. If an increase in line pressure causes an increase in noise, replace the oil pump.

Popping noise similar to popcorn popping

Oil pump system faulty and is allowing air into the system

First inspect the transaxle fluid filter for a leaky seam. Replace the fluid filter and fluid filter seal.

Next, inspect the transaxle fluid filter seal for improper positioning or for a cut seal. Replace the fluid filter and fluid filter seal.

Inspect the oil level control valve for proper operation or obstructions.

Finally, inspect for pump cavitation, indicated by bubbles in the fluid. Replace the pump if cavitation is found.

Buzz or high frequency rattle

Transaxle oil cooler line assembly is kinked

Verify a pressure buzz by watching for a needle vibration of the pressure gage. A road test may be necessary. Refer to Road Test . If pressure variation is found, inspect the oil cooler lines. Repair/replace as necessary.

Binding or contact at the radiator, other than at the cooler pipe connectors

Inspect the transaxle oil cooler line assembly routing and determine where contact is. Repair/replace the components as needed.

A whine or growl that increases and fades with engine speed and is most noticeable under light acceleration.

Drive link assembly system

Verify that the noise comes from the sprockets or from the drive link assembly, chain, by placing your left foot on the brake and by moving the gear selector from Park or Neutral. If the noise stops, check the following items.

Drive chain stretched

Replace the drive chain.

Drive sprocket and/or driven sprocket has broken or sheared teeth.

Replace the faulty sprocket.

Drive sprocket support and/or driven sprocket support has nicked or scored bearing surfaces.

Replace the faulty sprocket support.

Final drive noise is a noise or hum which is most noticeable under light throttle acceleration or turns.

Final drive and differential assembly could have worn final drive planet pinion gears.

The final drive and differential assembly has damaged differential side gear thrust washers.

Final drive and differential assembly could have worn final drive planet pinion gears.

Inspect the pinion thrust washers and replace as necessary.

Final drive sun gear worn or has damaged teeth.

Inspect the final drive sun gear and replace as necessary.

Final drive internal gear is worn or has damaged teeth.

Inspect the final drive internal gear and replace as necessary.

Final drive and differential assembly has worn or pitted differential pinion gears.

Inspect the differential pinion gears and replace as necessary.

Final drive and differential assembly has worn or pitted differential pinion gears.

Inspect the differential side gears and replace as necessary.

Final drive and differential assembly has worn or pitted differential pinion gears.

Inspect the differential side gears and replace as necessary.

Final drive and differential assembly has damaged differential side gear thrust washers.

Inspect the differential side gear thrust washers and replace as necessary.

Noise in all forward ranges: 1st, 2nd, 3rd, and 4th

Worn or damaged final drive sun gear

Inspect the final drive sun gear and replace as necessary.

Worn or damaged final drive planet pinion gear

Inspect the final drive planet pinion gears and replace as necessary.

Noise heard only in certain gear ranges (Random Noise)

Refer to Range Reference Chart in the Specifications portion of this service manual. Determine the power flow and applicable components that may be causing the noise.

Ratcheting noise

Parking lock pawl return spring is damaged, weak, or misassembled.

Inspect the forward clutch support assembly and repair/replace as necessary.