Hummer H2 2010 Owner's Manual page 340

Do not continue if the vehicle shudders or exhibits
suspension hopping. This can cause damage to
the driveline or suspension components. Improper
driving technique is not covered by the vehicle
warranty.
WARNING:
Turning or driving across steep hills can be
dangerous. You could lose traction, slide
sideways, and possibly roll over. You could be
seriously injured or killed. When driving up hills,
always try to go straight up.
Try to drive straight up the hill if at all possible.
If the path twists and turns, you might want to find
another route.
Ease up on the speed as you approach the top of
the hill.
Attach a flag to the vehicle to be more visible to
approaching traffic on trails or hills.
Sound the horn as you approach the top of the hill
to let opposing traffic know you are there.
Use headlamps even during the day to make the
vehicle more visible to oncoming traffic.
5-24
WARNING:
Driving to the top (crest) of a hill at full speed can
cause an accident. There could be a drop-off,
embankment, cliff, or even another vehicle. You
could be seriously injured or killed. As you near
the top of a hill, slow down and stay alert.
If the vehicle stalls, or is about to stall, and you cannot
make it up the hill:
Push the brake pedal to stop the vehicle and keep
it from rolling backwards and apply the parking
brake.
If the engine is still running, shift the transmission
to R (Reverse), release the parking brake, and
slowly back down the hill in R (Reverse).
If the engine has stopped running, you need to
restart it. With the brake pedal pressed, apply the
parking brake. If the vehicle has an automatic
transmission, shift the transmission to P (Park).
Restart the engine. Then, shift to R (Reverse),
release the parking brake, and slowly back down
the hill as straight as possible in R (Reverse).