GM Service Manual Online
For 1990-2009 cars only

Lubricant checks in this section also apply to these vehicles. There are two additional systems that need lubrication.

Transfer Case

When to Check Lubricant

It is not necessary to regularly check transfer case fluid unless you suspect there is a leak or you hear an unusual noise. A fluid loss could indicate a problem. Have it inspected and repaired.

How to Check Lubricant

Manual Transfer Case


Object Number: 809095  Size: B3

Automatic Transfer Case


Object Number: 807407  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, located on the transfer case, you will need to add some lubricant. Add enough lubricant to raise the level to the bottom of the filler plug hole. Use care not to overtighten the plug.

When to Change Lubricant

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

What to Use

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

Transfer Case

Vent Filter

The filter is attached to the transfer case vent tube. It is located on the driver’s side of the transfer case housing.

When to Change the Filter

Refer to the Scheduled Maintenance to determine how often to change the filter.