Tranny & Diff. Fluid Question

**Chuck M.** · August 31, 2005, 09:41 AM

Sorry the car is a '67 Coupe...

with an M20 Muncie. Also has Posi.

Thanks again

Chuck

**Duke W.** · August 31, 2005, 10:27 AM

Re: Tranny & Diff. Fluid Question

The original specification for each is Mil-L-2105D.

The modern equivalent is SAE 80W-90 GL-5.

Duke

**Jack W.** · August 31, 2005, 11:42 AM

Re: Tranny & Diff. Fluid Question

Rec you use the Posi additive from GM too.

**Duke W.** · August 31, 2005, 11:54 AM

Just in the axle. *NM*

**Jack W.** · August 31, 2005, 03:09 PM

Posi Additive to the Posi only, right! : ) *NM*

**Chuck M.** · September 1, 2005, 03:19 PM

Where is the best place to buy this?

Can I use the 80W-90 GL-5 in both tranny and diff? Thanks again for the help.

Chuck

**Duke W.** · September 1, 2005, 06:15 PM

That's the spec for both *NM*

**John H.** · September 2, 2005, 04:35 PM

Re: Where is the best place to buy this?

Chuck -

At your Chevy dealer - GM Diff Lube and GM Posi Additive.

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