Welcome to the Corvette Forums at the Corvette Action Center!

Differential fluid change

stevolwevol

Well-known member
Joined
May 28, 2015
Messages
250
Location
Michigan
Corvette
1977 light blue
I am preparing to replace the differential fluid in my 79 (Eaton). I've read some say always use GM additive, and I've also read using NAPA etc is fine also. Is there a real difference? Is there such a thing as too much additive? My plan is Valvoline GL5, plus NAPA additive. Input would be helpful.
 
I've never used anything other than GM lubes. The part numbers have changed over the years but the product is what is recommended for a GM posi rear axle. If the other brands meet the same specifications they should be alright. I can't say from experience though.

GM AC Delco Axle Lubricant 89021669

GM AC Delco Fluid 88900330 Limited Slip Axle Lubricant Additive.
 
I've never used anything other than GM lubes. The part numbers have changed over the years but the product is what is recommended for a GM posi rear axle. If the other brands meet the same specifications they should be alright. I can't say from experience though.

GM AC Delco Axle Lubricant 89021669

GM AC Delco Fluid 88900330 Limited Slip Axle Lubricant Additive.

Thank you Tom, I ended up taking the big leap and used the NAPA stuff. The differential and posi work fine. Thanks again.
 

Corvette Forums

Not a member of the Corvette Action Center?  Join now!  It's free!

Help support the Corvette Action Center!

Supporting Vendors

Dealers:

MacMulkin Chevrolet - The Second Largest Corvette Dealer in the Country!

Advertise with the Corvette Action Center!

Double Your Chances!

Our Partners

Back
Top Bottom