Rear Diff Fluid

[sbkim]

Greetings,

I've had big run around on this. I have a 2000 C5, 3.15. Initially, I had factory synthetic diff fluid. I had that chagned to Redline. Then the dealer convinced me to go with non-synthetic fluid. What is the recommended fluid for 2000 C5 - synthetic or non?

Thanks

 

[bluecoupe]

Fill the differential with fluid.
Use synthetic axle lubricant GM P/N 12378261 or equivalent meeting GM specification 9986115 to approximately 1.6 L (1.69 qt).
Use limited-slip differential lubricant additive GM P/N 1052358 or equivalent to approximately 118 ml (4.0 oz).
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.

 

[c4c5specialist]

HI there,
There was a TSB issued, to install non synthetic fluid in the Getrag differential, due to the fricitonal clutches chattering under tight turns. I think that this is where your dealership got their information.
Using conventional will NOT harm your differential in any way.
As long as you do NOT have a squealing noise under tight turns, in a parking lot, you will be just fine.
Also, bluecoupe is correct on the level, as if you put it right to the bottom of the fill hole, and the fluid gets really hot. As if you are autocrossing, or alot of high speed driving, the fluid will be forced out the vent, and you may experience a slight leak. 1/4 inch below the fill hole is correct.
Allthebest, c4c5

 

[sbkim]

Wow, great info!

Thank you very much! Given the price of these synthetic lubes, I will stick with non-synthetic assuming they do not make noises.

 

[bluecoupe]

Copy of an email I sent to Red Line:


What are the benefits of using Red Line vs. conventional fossil oil? Have there been any problems that you are aware of when using synthetic oil in a C5 Corvette rear-end?
Thanks
Frank

In the C5 differential I would recommend the Red Line 75W90, it
contains a friction modifier so additional shouldn't be necessary.
The benefits to the use of our product would be better wear
protection, so better durability, cooler operation, reduced friction
and loss for better performance. I am not aware of any issues when using the Red Line 75W90 in the C5 differential nor would I expect
any.

Regards, Dave
Red Line Oil