GM Service Manual Online
For 1990-2009 cars only

If you have an all-wheel-drive vehicle, be sure to perform the lubricant checks described in this section. However, there are two additional systems that need lubrication.

Transfer Case (Power Transfer Unit)

When to Check Lubricant

Refer to the Maintenance Schedule to determine how often to check the lubricant. See Scheduled Maintenance .

How to Check Lubricant


Object Number: 1254828  Size: B3

To get an accurate reading, the vehicle should be on a level surface.

If the level is below the bottom of the filler plug hole, you'll need to add some lubricant. Add enough lubricant to raise the level to the bottom of the filler plug hole, located on the transfer case.

What to Use

Refer to the Maintenance Schedule to determine what kind of lubricant to use. See Recommended Fluids and Lubricants .

Carrier Assembly-Differential (Rear Drive Module)

When to Check and Change Lubricant

Refer to the Maintenance Schedule to determine how often to check the lubricant and when to change it. See Scheduled Maintenance .

How to Check Lubricant

AWD Differential Case


Object Number: 1716440  Size: B3

  1. Fill Plug

  2. Drain Plug

To get an accurate reading, the vehicle should be on a level surface.

If the level is below the bottom of the filler plug hole, you'll need to add some lubricant. Add enough lubricant to raise the level to the bottom of the filler plug hole. A fluid loss could indicate a problem; check and have it repaired, if needed.

What to Use

Refer to the Maintenance Schedule to determine what kind of lubricant to use. See Recommended Fluids and Lubricants .