I just had this done on my 08 C6 and it made a big difference, I can't believe how used to the clunking and crunching noises I had become! I recommend having it done

 

I did the change out myself since it's out of warranty...quieted those clutch packs right down.

 

Had ours done about 1 month ago and it did make a big difference.

 

Under warranty. Same results, stopped grinding noise. I was begining to think a real problem was developing.
LJ

 

Thanks for the update. I have not heard anything yet and I hope I don't.

 

Had mine done in April

 

Had mine done in 2006..........

 

Mine was done about 6 months ago. Problem solved.

Here's the TSB, in case someone opens this thread looking for it:

TSB for Rear Differential Chatter:

Document ID# 2048181
2005 - 2008 Chevrolet Corvette

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Subject: Rear Axle Clunk and/or Chatter Type Noise on Turns (Drain/Refill Rear Differential Fluid) #07-04-20-002A - (01/09/2008)

Models: 2004-2008 Cadillac XLR (Including V-Series and Export)

2005-2008 Chevrolet Corvette (Including Z06 and Export)

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This bulletin is being revised to change the fluid recommendation and to remove the requirement of adding friction modifier. Please discard Corporate Bulletin Number 07-04-20-002 (Section 04 -- Driveline/Axle).

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Condition
Some customers may comment on a clunk and/or chatter type noise from the rear of the vehicle while making turns.

Cause
This condition may be caused by slip/stick of the posi-traction clutch plates due to insufficient limited-slip axle additive. As plates slip and stick, a jumping or jerking feel occurs accompanied by a clunk noise.

Correction
Important: DO NOT remove the differential cover from the rear or the two sides. It is not necessary to flush the old fluid from the differential.

Drain and refill the rear differential fluid using the procedure listed below.

Draining Procedure:

Raise and support the vehicle.
Clean any dirt from around the differential drain plug.
If not equipped with a differential cooler, remove the drain plug (1) and washer (2) from the differential.

If equipped with a differential cooler:
4.1. Using a bent tip screwdriver, remove the quick connect fitting retaining ring (3) from the quick connect fitting (4) and discard the retaining ring.

4.2. Remove the differential cooler inlet pipe from the differential nut.

Drain the fluid.

Filling Procedure:

If not equipped with a differential cooler, install the drain plug (1) and washer (2) to the differential.
Tighten
Tighten the differential drain plug to 35 N•m (26 lb ft).

If equipped with a differential cooler:
2.1. Install a new retaining ring.

2.2. Connect the differential cooler pump inlet pipe (2) to the differential. A distinct snap should be heard or felt when assembling the cooler pipe to the fitting.

2.3. To ensure the cooler line is properly installed, give the cooler pipe a gentle pull.

Clean any dirt from around the differential fill plug.
Remove the fill plug and washer from the differential.
Important: DO NOT add any limited-slip additive (friction modifier). With this new fluid (Dexron LS Gear Oil 75W-90) it is no longer required to add friction modifier. If friction modifier is added, it will cause the fluid to lose some of it's friction reducing properties as well as reducing seal life.

Fill the differential with the new DEXRON® LS gear oil, P/N 88862624 (Canadian P/N 88862625). Refer to the table listed below for lubrication specifications.
Check the fluid level to ensure it is even with the bottom of the fill plug hole to no lower than 6 mm (0.25 in) below the opening.
Install the fill plug and washer to the differential.
Tighten
Tighten the differential fill plug to 35 N•m (26 lb ft).

Important: Steps 8-13 are for vehicles equipped with the differential cooling system. For vehicles not equipped with the cooling system, proceed to step 14.

Raise the vehicle so the wheels are about a foot off the floor. Make sure the wheels can spin freely without obstruction from the hoist or any nearby items.
Start the vehicle and put the transmission in second gear. Slowly accelerate to 10 mph and hold this speed for one minute.
Turn the vehicle off .
Raise the vehicle.
Check the fluid level in the differential. Add fluid until the recommended level is reached.
Lower the vehicle.
Once the differential fluid has been changed, the vehicle must be driven in 8-10 tight figure eight maneuvers to heat the fluid and allow the fluid to be worked into the clutch plates.
Lubrication Specifications Application
Quantity

Metric
English

2004-2005 XLR (Including Export) and 2005 Corvette (Non Export)
1.72 liters
1.85 quarts

2006-2008 XLR (Including V-Series and Export) and 2006-2008 Corvette (Non Z06)(Non Export)
2.0 liters
2.11 quarts

2005 Corvette Export
1.88 liters
1.99 quarts

2006-2008 Corvette Export (Non Z06)
2.16 liters
2.28 quarts

2006-2008 Corvette Z06
2.75 liters
2.91 quarts


Parts Information
Part Number
Description

88862624 (US-1 Quart)

88862625 (Canada-1 Liter)
DEXRON® LS Gear Oil

Warranty Information
For vehicles repaired under warranty, use:

Labor Operation
Description
Labor Time

F9709*
Drain & Refill Rear Axle Fluid
0.6 hr

* This is a unique labor operation number for bulletin use only. It will not be published in the Labor Time Guide.


GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION


© Copyright General Motors Corporation. All Rights Reserved.


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Document ID# 2048181
2005 Chevrolet Corvette

 

 

The new DEXRON LS fluid is the solution. It became the factory fill for MY2009. I did my own fluid change 19 months ago with AMSOIL Severe Gear before DEXRON LS was available with identical results as the DEXRON LS. The real proof will be over the long term. AMSOIL Severe Gear has been working for me for 16k miles so far. For those with this problem, I would have the dealer do the change under warranty with the DEXRON LS. For the DIY, AMSOIL works also.

 

Is this for all c6's or just the manual 6spd models?

 

The design of the differential clutch packs is the same regardless of transmission type. The clunking/chattering differential problems have existed well before the C6 generation.

 

I have on 08 built April 28, 2008 and have heard no noises yet at 8,000 miles. Is anyone aware of the 08s not having this issue?

 

uhhhhh my dealer is saying they will have to charge me for this -- even tho I am still under warranty -- because GM is claiming this has to be done in the first 12 mos/12K miles ?!?!?!?!?!?!?!?!?!?!?!

 

I know several people with 08s that had the chattering problem. However, you may be reasonably fortunate and never have it. If you do eventually get it, the solution is very easy with the fluid change. My son has an 2008 (VIN 871) built April 28, 2008 as you. At 5k miles, no problem so far. From what I have heard, the chattering usually appears sometime between 5k & 10k miles. I don't know if GM changed over to DEXRON LS fluid prior to the end of MY2008 production or waited until MY2009 production start. I would love to hear that answer.

 

I would call this dealer . GM has not made any such claim to my knowledge. I think your dealer is trying to get into your pocket for more than what he would recover from GM as a warranty claim. I would call GM customer service to complain or find another dealer. Of course, the other option is DIY. If the clutches are chattering, the dealer & GM can either replace the clutches under warranty or do the fluid change under warrranty. I wonder which they will choose?? The first 12 mos/12K is the dealer's policy not GM's.

 

My 07 C6 was aprox 16 months old when it was handled under warranty.
LJ

 

I'm not surprised!!!

 

12 mos12k miles is only the bumper-to-bumper warranty. My understanding is that this differential TSB is covered under the powertrain warranty, which is longer (3 years 36k miles? Can't remember)

 

I had the work done at Classic, pleased with the service