This is very common and is a huge problem for GM. I am attaching the corporate bulletin below for you to read. You should still be under warranty, So have this performed. Make them document all your concerns as the condition will probably re-occur later. If they can't quiet it down then demand a new rear end. The condition is a fault in the rear end from the clutch pack. This rear end is VERY expensive so cover yourself good for future problems
This is the info that they don't want you to have, But now you do! Good luck!
Bulletin No.: 06-04-114-001A
Date: May 08, 2006
Moan/Groan Type Noise from Rear Axle During Parking Lot or Turning Maneuvers (Perform All-Wheel Drive (AWD) System Function Tests and Drain/Refill/Drive Procedure) Models:
2002-2006 Buick Rendezvous
2005-2006 Buick Terraza
2002-2005 Chevrolet Venture
2005-2006 Chevrolet Uplander
2002-2004 Oldsmobile Silhouette
2001-2005 Pontiac Aztek
2002-2005 Pontiac Montana
2005-2006 Pontiac Montana SV6
2005-2006 Saturn Relay
with Versatrak(R) All-Wheel Drive (AWD) System
This bulletin is being revised to correct fluid quantities in the Parts Information. Please discard Corporate Bulletin Number 06-04-114-001 (Section 04 - Driveline/Axle).
Some customers may comment on a moan or groan type noise coming from the rear axle during parking lot or turning maneuvers. The "AWD Disable" light should not be illuminated with this condition. Verify that the noise is originating from the rear axle with the chassis ears and/or by using a long rubber hose installed on the rear axle vent and held up to your ear.
This condition may be caused by a slip-stick condition between the friction and reaction plates in the clutch pack unit. This may be the result of wear or excess moisture within the unit.
Perform the all-wheel drive (AWD) system function tests and the drain/refill/drive procedure listed below.
|1. ||Disconnect the clutch pump actuator check valve connector. If the noise is eliminated, proceed to step # XXXXX If the noise is still present with the check valve disconnected, the condition may not be from the rear axle. The valve connector needs to be connected before continuing. |
|2. ||Verify that the tires are all the same size, make, and adequate tread depth. Repair as necessary. Drive the vehicle and re-evaluate the original concern and see if it is repaired. If not, continue with step # XXXXX |
|3. ||Perform the AWD System Functional Inspection tests as described in the published Service Information. If the system fails any of the functional tests, replace the rear axle assembly. Please document on the repair order which test or tests the system failed. If the system passed the functional tests, continue with step # XXXXX |
|4. ||Drain and Refill the rear axle with the recommended fluid, P/N 12378514 (88901045 in Canada), as described in the published service procedures. |
|5. ||Drive the vehicle for 20 minutes and perform the following maneuvers: |
|^ ||A: Drive a tight RH circle for 5 minutes. |
|^ ||B: Drive a tight LH circle for 5 minutes. |
|^ ||C: Repeat steps A and B. |
|6. ||Drain and refill the rear axle a SECOND time with the recommended fluid, P/N 12378514 (88901045 in Canada), as described in the published service procedures. Drive the vehicle normally to evaluate whether the noise has been corrected. |
These maneuvers are the only way to activate the rear axle clutch packs and pump the new fluid throughout the system. The system design will not activate the clutches when driving in a straight line, only a wheel speed difference between the two rear wheels will activate the georotor pump and flush the clutch packs.
Please follow this diagnostic or repair process thoroughly and complete each step. There will be some vehicles where the damage to the clutch packs from wear or moisture will be too extensive to be fixed by this procedure. In these cases, rear axle assembly replacement will be necessary.