GMC Hummer H3 2008 Owner's Handbook Manual page 196

R (Reverse)
Use this to back up.
NOTICE
Shift to R (Reverse) only after
your vehicle is stopped. Shifting
to Reverse while your vehicle is
moving could damage your
transmission.
The repairs would not be
covered by your warranty.
N (Neutral)
In this position, the engine doesn't
connect with the wheels. You can
use N (Neutral) to restart a stalled
engine while your vehicle is
moving.
CAUTION
Do not shift out of P (Park) or N
(Neutral) with the engine
racing.
You could lose control of the
vehicle and you or others may
be injured.
Section 3
NOTICE
Damage to your transmission
caused by shifting out of P
(Park) or N (Neutral) with the
engine racing is not covered by
your warranty.
195 . . .