Since I became an Amsoil dealer I have put the Severe Gear 75w-90 in my diffs and noticed a difference from the Mobil1 I had. I did not add any friction modifier to the fluid. Has been working great.

Ken

 

I found this posted here a while back stating to NOT use the limited slip additive and was said to be from GM. I changed mine with the the GM Synth and no addititive and did not notice any difference. Of course the GM stuff was rather expensive. I seem to remember about $25/quart and was about $35/quart list.

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INFO ON RECOMMENDED AXLE LUBRICANT #76-02-02A - (09/29/1998)
REVISION: 09/25/98 DIVS INVL 1 2 3 4 5 6 7

THIS BULLETIN IS BEING REVISED TO ADD THE 1998 AND 1999 MODEL YEARS AND ADD VEHICLE LINE AND RECOMMENDED AXLE LUBRICANT INFORMATION. PLEASE DISCARD CORPORATE BULLETIN NUMBER 76-02-02 (SECTION 0 - GENERAL INFORMATION). __________________________________________________ ____________________

SUBJECT: INFORMATION ON RECOMMENDED AXLE LUBRICANT

MODELS: 1999 AND PRIOR REAR WHEEL DRIVE PASSENGER CARS, LIGHT AND MEDIUM DUTY TRUCKS, AND FOUR WHEEL DRIVE VEHICLES

THE FOLLOWING TABLES PROVIDE THE LATEST INFORMATION ON RECOMMENDED AXLE LUBRICANT.

REAR AXLES WITH NON LIMITED-SLIP OR NON LOCKING DIFFERENTIALS

VEHICLE LINE RECOMMENDED AXLE LUBRICANT 1994 THROUGH 1997 CAMARO AND GM P/N 12345977 OR AN SAE FIREBIRD AND GEO (CHEVROLET) 80W-90 GL-5 GEAR LUBRICANT TRACKER

1998 AND 1999 CAMARO AND GM P/N 12378261, SAE 75W-90 FIREBIRD SYNTHETIC AXLE LUBRICANT

HD-3500 TRUCKS (DANA 11.0" GM P/N 12346140, SAE 75W-140 AXLES) SYNTHETIC GEAR LUBRICANT

CADILLAC CATERA GM P/N 12345977 OR AN SAE 80W-90 GL-5 GEAR LUBRICANT

1999 GMT 800 TRUCKS GM P/N 12378261, SAE 75W-90 SYNTHETIC AXLE LUBRICANT

ALL OTHER NON LIMITED-SLIP OR GM P/N 1052271 OR AN SAE NON LOCKING DIFFERENTIALS 80W-90 GL-5 GEAR LUBRICANT INCLUDING B AND D CARS, S/T, M/L, G, P, AND C/K TRUCKS EXCEPT GMT 800 TRUCKS, AND AS NOTED ABOVE

REAR AXLES WITH LIMITED-SLIP OR LOCKING DIFFERENTIALS

VEHICLE LINE RECOMMENDED AXLE LUBRICANT 1994 THROUGH 1997 CAMARO AND USE ONLY GM P/N 12345977 PLUS FIREBIRD, 1998 OR OLDER 4 OUNCES OF GM P/N 1052358 CHEVROLET CORVETTE LIMITED SLIP ADDITIVE

1998 AND 1999 CAMARO AND GM P/N 12378261, SAE 75W-90 FIREBIRD, 1999 CORVETTE SYNTHETIC AXLE LUBRICANT. WITH A COMPLETE DRAIN AND REFILL, 4 OUNCES OF GM P/N 1052358 LIMITED SLIP ADDITIVE

1996 AND OLDER B AND D CARS, USE ONLY GM P/N 1052271 PLUS AND 1993 AND OLDER CAMARO AND 4 OUNCES OF GM P/N 1052358 FIREBIRD LIMITED SLIP ADDITIVE

1999 GMT 800 TRUCKS GM P/N 12378261, SAE 75W-90 SYNTHETIC AXLE LUBRICANT (DO NOT ADD LIMITED SLIP ADDITIVE)
ALL OTHER LIMITED-SLIP OR USE ONLY GM P/N 1052271 LOCKING DIFFERENTIALS (DO NOT ADD LIMITED SLIP ADDITIVE) INCLUDING C/K (NON GMT 800), S/T, M/L, G TRUCKS

MEDIUM-DUTY TRUCKS (TOPKICK, KODIAK, ETC.)

VEHICLE LINE RECOMMENDED AXLE LUBRICANT MEDIUM DUTY TRUCKS GM P/N 12345841, SAE 75W-90 SYNTHETIC AXLE LUBRICANT FOR MEDIUM DUTY TRUCKS (EATON ROADRANGER AXLE LUBRICANT)

FRONT AXLES ON 4-WHEEL DRIVE VEHICLES

VEHICLE LINE RECOMMENDED AXLE LUBRICANT FRONT AXLES IN 4-WHEEL DRIVE GM P/N 1052271 OR AN SAE VEHICLES OTHER THAN GEO 80W-90 GL-5 GEAR LUBRICANT (CHEVROLET) TRACKER

FRONT AXLES IN 4-WHEEL DRIVE GM P/N 12345836, SAE 75W-90 VEHICLES IN COLD CLIMATES SYNTHETIC COLD CLIMATE FRONT WHEN EXCESSIVE SHIFT EFFORT AXLE LUBRICANT IS REQUIRED TO SHIFT INTO 4- WHEEL DRIVE

GEO (CHEVROLET) TRACKER GM P/N 12345977 OR AN SAE 80W-90 GL-5 GEAR LUBRICANT

PARTS INFORMATION:

PARTS ARE CURRENTLY AVAILABLE FROM GMSPO.

FIGURES: 00 ATTACHMENTS: 00

GENERAL MOTORS BULLETINS ARE INTENDED FOR USE BY PROFESSIONAL TECHNICIANS, NOT A "DO-IT-YOURSELFER". THEY ARE WRITTEN TO INFORM THOSE TECHNICIANS OF CONDITIONS THAT MAY OCCUR ON SOME VEHICLES, OR TO PROVIDE INFORMATION THAT COULD ASSIST IN THE PROPER SERVICE OF A VEHICLE. PROPERLY TRAINED TECHNICIANS HAVE THE EQUIPMENT, TOOLS, SAFETY INSTRUCTIONS AND KNOW-HOW TO DO A JOB PROPERLY AND SAFELY. IF A CONDITION IS DESCRIBED, DO NOT ASSUME THAT THE BULLETIN APPLIES TO YOUR VEHICLE, OR THAT YOUR VEHICLE WILL HAVE THAT CONDITION. SEE A GENERAL MOTORS DEALER SERVICING YOUR BRAND OF GENERAL MOTORS VEHICLE FOR INFORMATION ON WHETHER YOUR VEHICLE MAY BENEFIT FROM THE INFORMATION.

COPYRIGHT 1998 GENERAL MOTORS CORPORATION. ALL RIGHTS RESERVED.

 

Mort (Jim) is right about the G80. I went through all the confusion about the correct replacement gear oil when I put the TA Performance girdle on and was instructed to use the GM fluid as described by Mort with NO additive. This was per the dealership, by the way.