C5 Differential Fluid

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Apr 29, 2021 | 09:24 PM

Black03vert

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C5 Differential Fluid

I searched and read every thread on Corvette C5 differential fluid. It's time to bring this topic into the 2020s with new products available.
Is this an approved fluid for the Corvette C5? What is the GM recommended fluid at this time?

GM Part #88862624
AC Delco 10-4034 75W-90 DEXRON

Apr 30, 2021 | 12:13 AM

1BadLS6

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From: Berthoud, CO

I recently bought a built rear diff from RKT Performance and this is what he told me to use. I did and so far no issues. I'd say Rick knows what he's talking about.

Apr 30, 2021 | 08:18 AM

Kubs

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From: Akron Ohio

2025 Corvette of the Year Finalist - Modified

2024 C5 of the Year Winner - Modified

2023 C5 of the Year Finalist - Modified

2022 C5 of the Year Finalist - Modified

St. Jude Donor '09-'10-'11

I use AMSOIL Severe Gear 75W-90 fluid in several C5 track cars, street cars, heck even in my truck I use to tow the track car. It has the appropriate amount of limited slip additive already so no need to buy extra.

https://www.amsoil.com/p/severe-gear...vg/?zo=1934716

Apr 30, 2021 | 09:41 AM

Jon1230

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From: Atlanta

I used the 88862624 ACDelco in my 2001. Took two quarts (like 95% of the second quart) and it works fine. No chatter or any other noises.

Apr 30, 2021 | 04:55 PM

pjdbm

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From: Long Island New York

I did AMSOIL Severe Gear 75W-90 fluid twice with great results and never needed to add limited slip lubricant to it.

May 1, 2021 | 07:40 PM

oh1vette

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From: Youngsville North Carolina

^^^^^^^

May 1, 2021 | 08:44 PM

Javybaez

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Always stick with oem fluids.

May 2, 2021 | 11:42 AM

grinder11

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Quote:

Originally Posted by Javybaez

Always stick with oem fluids.

I agree. Just go to the dealer, give them your model year car, tell them what you want, presto: you'll get 2 quarts of OEM fluid. My original OEM gear lube went 110,000 miles. Bought OEM again. If it ain't broke, don't fix it.....

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May 3, 2021 | 07:54 AM

Kubs

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From: Akron Ohio

2025 Corvette of the Year Finalist - Modified

2024 C5 of the Year Winner - Modified

2023 C5 of the Year Finalist - Modified

2022 C5 of the Year Finalist - Modified

St. Jude Donor '09-'10-'11

Quote:

Originally Posted by Javybaez

Always stick with oem fluids.

Im curious why you think so? OE is constantly a battle between the engineering department and the finance department. Its not always the BEST. I dont run a single OE fluid in my car because it will overheat and break down on track way sooner than a proper aftermarket fluid. A lot of technology has happened since the C5 was developed. Even for normal street driving there a better fluids for longer life, better rolling resistance (fuel mileage), smoother shifts, better cold properties, etc.

May 3, 2021 | 08:42 AM

#10

oharal

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From: CSRA, SC

Quote:

Originally Posted by Javybaez

Always stick with oem fluids.

*Maybe if your car is under warranty...

Another vote for the Amsoil product. Never had an issue in 50k of street and track use.

May 4, 2021 | 12:15 PM

#11

Black03vert

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I want to stick with the OEM fluid, however there has been part number changes and this newer AC Delco product, there is no clean way to determine what is the current factory recommendation.

May 5, 2021 | 11:10 AM

#12

Javybaez

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This is the correct diff fluid.

May 6, 2021 | 10:48 AM

#13

grinder11

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Quote:

Originally Posted by Javybaez

This is the correct diff fluid.

That looks like what I'm running. The older Dexron got me 100,000 trouble free miles. Rear end is like new, no clunks, no excessive backlash. So I used it again when I changed out the gear lube at 100 thousand miles. I mean, how many cooked C5 gears do we see with the OEM fluid? I've never seen even 1 that could be attributed to insufficient quality of the OEM gear lube/friction modifier. Sometimes the transmission blows the rear diff right off of it, separating the diff from the trans. But that's not a gear lube related failure. More like a 5,000rpm clutch drop at the track, while running 11" wide slicks!!!