Launch Shudder/Vibration on Acceleration (Replace Propeller Shaft and InstallNew Pinion Flange/Seal)

This bulletin is being revised to add Model information. Please discard Corporate Bulletin Number 02-04-17-001 (Section 04 -- Driveline Axle).

Important: Implementation of this Service Bulletin by "GM of Canada" dealers requires prior District Service Manager approval.

Some customers may comment on a vibration when accelerating from a stop. This is also known as launch shudder. This condition may occur between 0-40 km/h (0-25 mph) and be more noticeable when the vehicle is carrying cargo or used for towing.

A new propeller shaft, P/N 15071486, has been developed to correct this condition. The new propeller shaft incorporates dual double cardan joints on the center and rear joint positions. Refer to Corporate Bulletin Number 02-00-90-002 for lubrication information.

The new propeller shaft will require the installation of a new pinion flange kit, P/N 15071485. The pinion flange kit consists of the following components:

Replace the propeller shaft with the new propeller shaft using the following procedure. Use the part numbers listed below.

1. Remove the propeller shaft assembly and the center bearing. Refer to the applicable Propeller Shaft Replacement procedure in the Propeller Shaft sub-section of the Service Information (SI).

Important: In step 2, you must measure the pinion and differential preload. This information is needed to set the preload of the new pinion flange to the correct specification and to reduce any rear axle noise concerns.

2. Remove the drive pinion yoke and the pinion oil seal. Refer to the Drive Pinion Flange/Yoke and/or Oil Seal Replacement procedure in the Rear Drive Axle sub-section of the Service Information (SI).

Important: In step 3, use this procedure as a guideline to install the pinion flange to the drive pinion and to set up the proper pinion bearing preload.

3. Install the new pinion oil seal, the new pinion flange and the new drive pinion nut. Refer to the Drive Pinion Flange/Yoke and/or Oil Seal Replacement procedure in the Rear Drive Axle sub-section of the Service Information (SI).
4. Install the new propeller shaft assembly and the new center bearing. Refer to the applicable Propeller Shaft Replacement procedure in the Propeller Shaft sub-section of the Service Information (SI).

Tighten

•	Tighten the propeller shaft flange bolts to 70 N·m (52 lb ft).

•	Tighten the center bearing support nuts to 40 N·m (30 lb ft).

5. After completing the repair, operate the vehicle in order to verify that the condition has been corrected.

*Parts are included in Flange Kit P/N 15071485.

Parts are currently available from GMSPO.

For vehicles repaired under warranty, use: