Differential Fluid

[Tim Keeler]

I need the G.M. part number for the rear end lube for my 73. I've got the G.M. additive but I can't come up w/ the PN for the diff. fluid. As always, Thanks, Tim #26883

[Duke W.]

Re: Differential Fluid

My 1984 vintage GM Standard Parts Catalog lists 24 oz. bottles of axle lubricant as p/n 1052271, and the four oz. bottle of "whale sperm" positraction additive as 1052358. If these part numbers have been superceded, the GMPD electronic database should have the new numbers, or Joe will post the latest. If memory serves me correctly the Corvette diff holds approximately 3.7 pints, so you'll need three bottles of the gear oil. Also, it's best to use the minimum amount of additive required to prevent chatter, so you might start out with just two oz. of additive and only add more if there is chatter. The more additive, the "looser" the the limited slip action. Another alternative is Redline 75W-90 gear oil, a synthetic GL-5 lubricant that contains the necessary friction modifiers for limited slip diffs, which eliminates the need for the additive. Users I have talked to report excellent results with GM clutch and cone type positration units.

Duke

[Joe L.]

Re: Differential Fluid

Duke-----

As far as I know, the part numbers which you posted are the current ones. These are ancient part numbers, but they've remained the same.


Cranes Corvette

[motorman]

Re: Differential Fluid

amsoil gear lube will work just fine. i have been using it since it came out with great results in posi rear gears.

http://clemz9@hotmail.com

[Mike hom]

Re: considered a synthetic?

Many have been convinced that synthetic lubricants are superior to their petroleum based cousins. I'm suprised Joe did not take the opportunity to plug synthetics, he has stated several times that he is a fan. I have the red line product in both the 65 and the zr-1. No chatter, what else is there other than trouble free operation in the short term and longer useful life?

As an aside, when I bought the red line, I got it from a guy who builds racing rear ends for a living (including a couple of nascar contracts). He's been building and rebuilding differentials as his sole source of income for over 25 years he says. He said he is absolutely sold on the red line heavy shockproof lubricant, although the positratcion additive must be added separately. He says he uses it in every unit he rebuilds. He was out of it when I was there so I opted for the regular red line differential lube which already contains the friction modifier. Your choice but the synthetic seems like cheap insurance. Maybe other members have experiences to share.

[Michael W.]

how about P/N 10950849?

That's what my local GM dealer stocks, and I've been using for ? years. Would this be a GM Canada only P/N?

Mike


Quebec NCRS Chapter

[Joe L.]

Re: how about P/N 10950849?

Mike----

That must be a GM-Canada part number only. It's not even listed in the GM parts information which I have. It's probably a metric unit package for the same stuff.

[Gary Schisler]

Agree with synthetic!

I have been using Mobil 1 synthetic diff. lube since I first saw it. Of course, I add the GM brand of posi. additive.