79 posi differential

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Jul 31, 2012 | 07:53 AM

nashdavea

Thread Starter

Heel & Toe

Joined: Apr 2011

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79 posi differential

I've been reading threads about posi differntial lube and additive and I decided to use the original 1052271 oil and 1052358 additive. So I call my local Chevy dealer and he says the 1052271 is no longer avail and it's superceded to a new part number and he doesn't carry the additive. Anyone know if this is some new and improved oil ($23 per quart). Is there a GM tech bulletin about the new oil and additive/no additive? Is the new stuff really just Amsoil or one of the other synthetics that so many have suggested on the threads? Should I just follow the advice of those who are using other types of synthetic oil with no additive? Advance auto sells K & W Chemical Trans-X® Posi-Trac® Limited Slip Gear Oil Additive 7oz for $5.69.

Any suggestions? Thanks

Jul 31, 2012 | 08:58 AM

jb78L-82

Le Mans Master

Joined: Oct 2007

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From: Tennessee/Rhode Island

I have been using Mobil 1 75W-90 synthetic for 22 years with no additive and zero issues. Just my example.

Jul 31, 2012 | 09:02 AM

Marlin

Drifting

Joined: Aug 2005

Posts: 1,372

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From: Springfield VA

Yea many have used the M1 75w-90 in the rear diffs. Has the POSI additive already in it.

Jul 31, 2012 | 10:04 AM

brando1118

Pro

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Quote:

Originally Posted by jb78L-82

I have been using Mobil 1 75W-90 synthetic for 22 years with no additive and zero issues. Just my example.

No muss, no fuss. Mobile one synthetic gear oil with the "LS" designation. I recently installed a rebuilt diff and that is what went into it. Nice and smooth and quiet.
No additive is necessary.

Jul 31, 2012 | 11:04 AM

Mike Ward

Race Director

Joined: Jul 2001

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You don't need a 'quart' of the additive- GM sells it in little 4 oz bottles for 7-9 bucks or so.

Jul 31, 2012 | 04:29 PM

63mako

Race Director

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From: Millington Illinois

St. Jude Donor '08-'09

I have been using Amsoil 80W-90 with no additive for 12 years in 4 different differentials, 2 old, 2 rebuilt. Never an issue. $20 for a fill. The "new and improved" GM is $23 a quart x 2 + $9 for additive. $55 for a fill. It better be "new and improved"! FWIW GM does not manufacture gear oil. It is repackaged from another manufacturer.

Last edited by 63mako; Jul 31, 2012 at 04:34 PM.

Aug 1, 2012 | 09:19 PM

C66 Racing

Premium Supporting Vendor

Joined: Aug 2001

Posts: 5,364

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From: King George VA

Quote:

Originally Posted by nashdavea

... Is the new stuff really just Amsoil or one of the other synthetics that so many have suggested on the threads?

Not AMSOIL, and as 63mako mentions the AMSOIL is less than the GM stuff.

AMSOIL Synthetic Gear Lube SAE 80w90 (Product Code AGLQT)

No extra additive needed.

More than happy to get AMSOIL products for forum members at dealer wholesale pricing, about 25% below retail, via the AMSOIL Preferred Customer Program. Drop me a PM if interested.