differential GMC SIERRA 2008 Owner's Manual

How to Check Lubricant
To get an accurate reading, the vehicle should be on
a level surface.
A:Fill Plug
B:Drain PlugA:Fill Plug
B:Drain Plug
When the differential is cold, add enough lubricant
to raise the level from 0 (0 mm) to 1/8 inch (3.2 mm)
below the ller plug hole.
When the differential is at operating temperature
(warm), add enough lubricant to raise the level to
the bottom of the ller plug hole.
What to Use
Refer to the Maintenance Schedule to determine what
kind of lubricant to use. SeeRecommended Fluids
and Lubricants on page 6-15. 1500 Series
2500 Series
5-55