Two Piece Propshaft Launch Shudder

When servicing the vehicle with the VIN you entered, the following diagnosis might be helpful if the vehicle exhibits the described symptoms.

1. Launch shudder/shake on acceleration.
2. The launch shudder usually occurs between 4-20 mph.

Prior to performing any repairs:

1. Compare to like vehicles.
2. Compare driveline working angles with a vehicle exhibiting less launch shudder.
3. Some launch shudder is characteristic on S10 pickup 4 cylinder models with the two piece propshaft.

Repair recommendation #1.

1. Check and record the driveline working angles.
2. Install transmission mount P/N 22145732. This mount is used on 99-02 V-6 equipped 2WD S10 models. The part number shown is the most current at the time of this information. Part numbers are subject to change.
3. After torqueing the mount to specifications ensure the mount does not directly contact the cross member. It may be necessary to grind a portion of the mount to prevent a ground out condition.
4. Re-check the driveline working angles to ensure they are at the previous recorded readings.
5. If the driveline working angles are not at the previous recorded readings it may be necessary to install part number 1254001 which is a 1/8 in. shim. Installing this shim will change the transmission angle approximately a 1/2 degree. Depending upon the suspension package, it may be necessary to install two 1/8 in. shims.
6. Road test to ensure the launch shudder is reduced and no other vibration concerns occur.
7. If the launch shudder is not reduced, refer to repair recommendation #2.

Repair recommendation #2.

1. Remove the rear propshaft.
2. As viewed from the rear of the vehicle looking forward re-install the propshaft seven splines counter clockwise.
3. If no improvement after clocking the propshaft seven splines counter clockwise begin by reversing the procedure one spline at a time.
4. Road test to ensure the launch shudder is reduced and no other vibration concerns occur.

Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance. This diagnostic approach was developed for the vehicle with the VIN you entered and should not be automatically be used for other vehicles with similar symptoms.