Hummer 2004 H2 Owner's Manual page 363

How to Check Lubricant
A. Filler Plug
B. Drain Plug
1. Remove the filler plug (A). The fluid level should be
just below the bottom of the filler plug hole. To get
an accurate reading, the vehicle should be on a
level surface.
2. Add fluid if necessary.
Refer to the Maintenance Schedule to determine
what kind of lubricant to use. See Recommended
Fluids and Lubricants on page 6-12.
3. Reinstall the filler plug. Use care not to overtighten
the filler plug.
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