EI08246 - 11.5 Rear Axle Ring Gear Growl or Grind Noise Caused by Pinion Tail Bearing (Engineering Information
| Subject: | EI08246 - 11.5 Rear Axle Ring Gear Growl or Grind Noise Caused by Pinion Tail Bearing (Engineering Information) |
| Models: | 2008 Chevrolet Silverado 2500HD and 3500 Series Only |
| 2008 GMC Sierra 2500HD and 3500 Series Only |
| with Allison® 1000 Transmission (RPO MW7) and 11.5 Rear Axle Ring Gear |
| Built AFTER January 1, 2008 |
| Attention: | Dealers located in U.S. and Canada ONLY -- Proceed with this bulletin ONLY if the customer has commented about this concern AND the EI number is listed in GMVIS. If the customer has not commented about this condition or the EI does not show in GMVIS, disregard the bulletin and proceed with diagnostics found in published service information. THIS IS NOT A RECALL -- refer to TSB 04-00-89-053B for more detail on the use of Engineering Information bulletins. |
Condition
Some customers may comment on a growl or grind noise from the rear axle assembly.
What Action to Take
Important: This request only relates to pickup trucks equipped with the 11.5" rear axle with build dates AFTER January 1, 2008.
GM Engineering is attempting to determine the root cause of the above condition. GM Engineering would like to receive product feedback on 2008 Chevrolet Silverado and GMC Sierra 2500HD and 3500 Series vehicles exhibiting a growl or grind noise from the rear axle assembly caused by the pinion tail bearing that have not been serviced previously for this concern. As a result, this information will be used by engineering to "root cause" the customer's concern and develop/validate a field fix.
Instructions
Important: DO NOT attempt to repair or service the rear axle assembly. It is important that the rear axle is not disturbed.
If a vehicle is encountered with the above concern, please follow these steps:
- Make sure the complete VIN and mileage are recorded accurately on the repair order.
- Record the vehicle build date (Information can be found in GMVIS).
- Confirm that the noise is coming from the rear axle assembly and is caused by the pinion tail bearing. Inspect for a seized pinion, or axial or radial movement of the pinion flange. Refer to Rear Drive Axle Noises in SI.
- Verify the axle has not been previously serviced for this concern.
- Contact either engineer -- Rich Burrell (586-947-5740) or Rob Rearick (269-506-7438) (alternate contact) and provide the following information:
| 5.1. | Technician Name, Dealer Name and Dealer Code |
| 5.2. | City and State |
| 5.3. | Complete VIN |
| 5.4. | Repair Order Number |
| 5.5. | Dealership phone and fax numbers |
If engineering is unable to return the call within one hour, proceed with diagnosis and repair based on information found in SI.
Warranty Information
For vehicles repaired under warranty, use:
Labor Operation | Description | Labor Time |
|---|---|---|
F9720* | Rear Axle Assembly -- Engineering Information | 3.3 hrs |
* This labor operation number is for bulletin use only. This number will not be published in the Labor Time Guide. | ||
