Rear Axle - GMC 2003 Yukon Owner's Manual

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 .

Rear Axle

When to Check Lubricant
Refer to the Maintenance Schedule to determine how
often to check the lubricant. See Part A: Scheduled
Maintenance Services on page 6-4 .
5-50
How to Check Lubricant
1500 Series shown, 2500 similar
To get an accurate reading, the vehicle should be on a
level surface.
The proper level for the 1500 Series is from 5/8 inch to
1 5/8 inch (15 mm to 40 mm) below the bottom of
the filler plug hole. The proper level for the 2500 Series
is from 0 to 1/2 inch (0 to 13 mm) below the bottom
of the filler plug hole. The proper level for the 1500 and
2500 series vehicles with QUADRASTEER™ (4
Wheel Steer) is from 0 to 1/4 inch (0 to 6 mm) below
the filler plug hole. Add only enough fluid to reach
the proper level.