Hummer 2004 H2 Owner's Manual page 127

Adjusting the Crossrails
Adjust the crossrails to fit your load by doing the
following:
1. Loosen the lock knobs on the crossrail supports by
turning the knobs counterclockwise. Only loosen
them enough to allow the crossrails to slide easily.
2. Slide the crossrails to the desired position, being
sure to align the lines in the side rails with the
arrows on the crossrail supports.
3. Tighten the lock knobs and then try to move the
crossrails back and forth to be sure that they do
not move.
4. Once you load the cargo onto the crossrails, secure
it by tying it down to the crossrail support cargo
tie-down loops. Do not load cargo directly on
the roof of your vehicle.
Be sure you do not cover the roof marker lamps or
the Center-High-Mounted Stoplamp (CHMSL) (If
equipped) with cargo.
To prevent damage or loss of cargo check now and
then to make sure the luggage and cargo are still
securely fastened and the crossrails are tight.
Stop Tabs
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