Info - Rear Axle Lubricant Compatibility and Usage
| Subject: | Rear Axle Lubricant Compatibility and Usage |
| Models: | 1988-99 Chevrolet and GMC C/K, G Van and P1-3 Series Models |
| 1999 Cadillac Escalade |
| Built after the VIN Breakpoints (C/K) listed below: |
This bulletin is being revised to add the 1999 Model Year, VIN Breakpoint information, and additional text. Please discard Corporate Bulletin Number 86-42-04 (Section 4 - Driveline/Axle).
Plant | Make | VIN Breakpoint |
|---|---|---|
Arlington | Chevrolet (Pickup) | XR703077 |
Arlington | Chevrolet (Pickup) | XR703078 |
Arlington | Chevrolet (Tahoe-4 Dr) | XR148860 |
Arlington | Cadillac (Escalade) | XR409680 |
Arlington | GMC (Pickup) | XR703184 |
Arlington | GMC (Pickup) | XR703113 |
Arlington | GMC (Yukon-4 Dr) | XR516469 |
Arlington | GMC (Denali) | XR914788 |
Flint | Chevrolet (All) | XF062378 |
Flint | GMC (All) | XF062366 |
Janesville | Chevrolet (All) | XJ471026 |
Janesville | GMC (All) | XJ771410 |
Silao | Chevrolet (Tahoe-2 Dr) | XG206200 |
Silao | Chevrolet (Tahoe-4 Dr) | XG206323 |
Silao | GMC (Yukon-4 Dr) | XG534060 |
This bulletin is being issued to inform dealers about the compatibility and usage of the new Fuel Efficient SAE 75W-90 Synthetic Axle Lubricant, GM P/N 12378261 (In Canada use P/N 10953455), with current axles, and with the non-synthetic axle lubricant, GM P/N 1052271 (In Canada use P/N 10950849), for the rear axles on the above light-duty trucks.
Testing has shown that the new synthetic lubricant will chemically attack the Room Temperature Vulcanizing (RTV) sealant. Use only the non-synthetic lubricant, P/N 1052271, in axles using RTV sealant (See 9.5 and 10.5 information below).
American Axle and Manufacturing (A.A.M.) has approved the use of the new Fuel Efficient SAE 75W-90 synthetic axle lubricant for rear axles with the following restrictions:
| • | All 8.6 inch axles are compatible as originally built. |
| • | 9.5 inch axles on vehicles built prior to mid-February 1998 are NOT compatible because RTV sealant is used on the cover pans. |
| On vehicles built after mid-February 1998 and equipped with 9.5 inch rear axles, synthetic lubricant, P/N 12378261, can be used because the RTV was replaced with a gasket. Other mid-February changes to the 9.5 inch rear axles include a new cover pan and cover pan fasteners common to other axles. |
| Important: The new cover pan is not retrofittable to the housing of 9.5 inch axles on vehicles built prior to mid-February 1998. A new retrofit kit is available that will enable the use of synthetic lubricant for vehicles built after mid-February, 1998. |
| • | All 10.5 inch axles prior to March 3, 1999 are compatible if the axle shaft hub seal (RTV) is replaced with P/N 327739 gasket when changing to synthetic lubricant. |
As a product improvement, this new lubricant has been released into 1999 current production C/K vehicles built after the above VIN breakpoints (Except HD3500 models which use 75W-140 synthetic lubricant, P/N 12346140).
It is recommended that synthetic lubricant be used when changing rear axle lubricant for the following reasons:
| • | Potential fuel economy |
| • | Lower operating temperature under severe usage conditions |
Important:
• You do not need to wash/rinse any non-synthetic lubricant from
the axle cavity when changing over to a synthetic lubricant. However, you
should remove debris from the magnet and the bottom of the axle cavity whenever
the axle fluid is changed. • On light-duty trucks equipped with locking differentials, do NOT
use a limited-slip additive.
Parts Information
P/N | Description | Quantity |
|---|---|---|
327739 | Gasket, Axle Shaft Seal | 1 |
12378261 (In Canada use P/N 10953455) | Fuel Efficient SAE 75W-90 Synthetic Axle Lubricant | 1 |
1052271 (In Canada use P/N 10950849) | Non-Synthetic Lubricant | 1 |
12471310 | Kit, 9.5 Inch Axle Cover Pan | 1 |
Parts are currently available from GMSPO.
