Ok, so I purchased a 06 A6 in July of 2006. Took it to the dealer in December 2006 with 2K miles for the rear end noise (clutch packs) and they did the additive to the differential. One year later, with 11K miles it started making the noise again. Took it back to the same dealer and was told that there has since been an “upgraded” additive and that it should be fixed this time (in addition to the fabric on my top separating, the fan control button sticking, and my chimes not always working). Since getting it back I have not really had a chance to drive it due to the rain here in San Diego, but it was not making the noise when I got it back. My question to some of the more knowledgeable people is did the service department BS me about some new improved additive that came out three months ago? Also, I am concerned that in another year and a half I will no longer have the warranty (only 3 years) and want this problem fixed for good. What would you guys do if the noise comes back again?

Thanks and all responses welcome.

 

Drain the differential and replace it with Amsoil 75-90 severe duty synthetic.

 

and do your figure 8s

 

and also add 4oz Amsoil slip lock and all your rear end noise will be gone (at least it is for me).

 

GM was working on am improved lubricant, not an additive. I do not think it is out yet. I thought it was going to be a few more weeks.

All they are doing right now is adding 8 oz. of additive, instead of 4 oz. of additive with the fluid change.

Just check the GM part numbers on your copy of the repair order to see what they used. Let me know.

 

Thank you all for the answers. Looking at the invoice:
G20 Differential
18 WAR5 0.60 (N/C)
2 89021677 gear lubr (N/C)
2 Misc Additive (N/C)
10800 Differential clutch chatter F9709=.6 Changed differential fluid and added updated friction modifier per service information #07-04-20-002. Then drove vehicle in ten figure eights. May take several hundred miles for friction modifier to work.

There is more, but it concerns my A/C control unit and other items. So, what do you think? Does that sound like they did the new treatment?

thanks again! Did I mention that I love this forum? It is an absolute wealth of knowledge.

Jeff

 

The latest TSB calls for 8oz of additive instead of 4oz. like stated before. The "updated friction modifier" that is mentioned in your post is probably just the updated TSB calling for two 4oz treatments instead of the original one.

 

Question: What is the Part Number for the "2 Misc Additive (N/C)".

Every GM part and fluid has a GM part number. If they did not use the GM limited slip additive, PN 1052358, what did they use??

As per #07-04-20-002, the conditioner PN 1052358 is the same stuff used for years.



Document ID# 1961528


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Subject: Rear Axle Clunk and/or Chatter Type Noise on Turns (Drain/Refill Rear Differential Fluid and Add Specified Limited-Slip Axle Additive) #07-04-20-002 - (04/16/2007)



Models: 2004-2007 Cadillac XLR (Including V-Series and Export)

2005-2007 Chevrolet Corvette (Including Z06 and Export)




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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. Add the increased amount of limited-slip axle additive specified below.





Raise and suitably support the vehicle.
Clean any dirt from around the differential drain plug.
Remove the drain plug and washer from the differential.
Drain the fluid.



Install the drain plug and washer to the differential.
Tighten
Tighten the differential drain plug to 35 N·m (26 lb ft).





Clean any dirt from around the differential fill plug.
Remove the fill plug and washer from the differential.
Important: Prior to adding the limited-slip axle additive, the bottle MUST be shaken vigorously for at least 1 minute to mix the additive thoroughly, then immediately poured into the differential.

Add 237 ml (8.0 oz) limited-slip axle additive, P/N 1052358 (Canadian P/N 992694).
Fill the differential with synthetic axle lubricant, P/N 89021677 (Canadian P/N 89021678).
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).

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 additive to be worked into the clutch plates.
Parts Information
Part Number
Description
Qty

89021677 (89021678 In Canada)
Synthetic Axle Lubricant
2 (3 for Z06 and Export)

1052358 (992694 In Canada)
Limited-Slip Axle Additive
2


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# 1961528

 

Many of us have been through the same issues as you. Your best bet is to do the Amsoil change. Many of us have had great success with this change. I have not heard of anyone having the chatter come back after switching to Amsoil. See the following thread for more info. http://forums.corvetteforum.com/show....php?t=1732382