Chevrolet TrailBlazer 2003 Manual page 333

How to Check Lubricant
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.
Use care not to overtighten the plug.
What to Use
Refer to the Maintenance Schedule to determine what
kind of lubricant to use. See Part D: Recommended
Fluids and Lubricants on page 6-17.
Front Axle
When to Check and Change Lubricant
Refer to the Maintenance Schedule to determine how
often to check the lubricant and when to change it.
How to Check Lubricant
To get an accurate reading, the vehicle should be on a
level surface.
5-49