I'm confused??? Not an unusual situation for me!! I went to a dealer in a small town and asked about changing the fluid in my diff. I have a 2006 base car with Z51 option. I was told that he would have to order the additive so I would need to come back after he had obtained the necessary additive. I think I read some where that the additive is no longer used and problem can arise if it is used with the new type of diff fluid. Right or wrong?? What is the correct fluid? Thanks

 

Ask your question here if you don't get a satisfactory answer in this forum.

https://www.corvetteforum.com/forums...rformance-101/

 

AC Delco part #88862624
Dexron LS Gear Oil
75W90

No additives needed. This is what is noted in the GM TSB. You may want to speak to the service manager about the info you were given about your car.

 

Here is a pic of the bottle. They should have this in their parts department.

 

These guys are right. If dealer says you need additive with GM oil, he's got the wrong lube.

Not rocket science here...

 

Good luck with this one. It has been kicked around the forum on many occasions and the difference in opinions is mindboggling (sp). This dealers right....that dealers wrong....don't use additive....do use additive. Use only GM lube....use only a good aftermarket....etc....etc. You're really in a damned if you do and damned if you don't situation cause no matter what you decide to put in it there will be people telling you you did the wrong thing. The most common "Universal" advice seems to be put in a good quality grade synthetic that has the additive already in it. Regardless, just be ready to juggle all the post telling you that you should do what they suggest.

 

This is the Lube you need, it has all the necessary additives already in it!! You will need about 3 quarts of the stuff. Its about $10.00 /Qt!

 

Actually, it's been "solved" as a problem by GM for all our C6s and other cars as well for about the last four years. The fluid was breaking down; they tried different additives, finally coming up with the right amount. That means, one fluid, additive already in the bottle. End of problem. As shown above, get the right bottle, and advise the service manager that wrong info is being given out which is never good.

 

But the poor Dealers are sitting on inventory of the old fluid. Aren't we supposed to be ignorant consumers and pay for what they want to sell us?

 

Yup. But only if CF allows them to be ignorant, and I know you wouldn't let that happen.

 

This is the new stuff...no additive needed:



And it is expensive, so don't be surprised at the price.

 

There is no confusion on this at all. There is a GM TSB that resolved the problem and clearly defined the repair procedure. OP's dealer is wrong.

 

This is the actual applicable TSB from GM in its entirety:

"Here's the TSB:

Document ID# 2048181
2005 - 2008 Chevrolet Corvette

--------------------------------------------------------------------------------

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)

--------------------------------------------------------------------------------

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).

--------------------------------------------------------------------------------

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."

 

Remember to do those tight "figure eights" in the parking lot to get the fluid into the clutch pack plates! Most people are NOT aware of this step, most important!

 

This is what I used also...worked great.

 

 

Excellent reminder!

 

 

This is 100% correct.

 

This is kinda an oxy-moron isn't it ?? You say theres no confusion at all but then you say that the OP's dealer is wrong....interesting.