Four-Wheel Drive - Hummer 2006 H2 Owner's Manual

How to Check Lubricant
To get an accurate reading, the vehicle should be on a
level surface.
When the differential is cold, the proper level is from
5/8 inch to 1-5/8 inch (15 mm to 40 mm) below the
bottom of the filler plug hole, located on the rear axle.
Add only enough fluid to reach the proper level.
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What to Use
Refer to the Maintenance Schedule to determine what
kind of lubricant to use. See Recommended Fluids
and Lubricants on page 6-12.

Four-Wheel Drive

Transfer Case
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.
Refer to the Maintenance Schedule to determine how
often to change the lubricant. See Scheduled
Maintenance on page 6-4.