Hummer 2006 H3 Owner's Manual page 226

Q:
Suppose, after stalling, I try to back down the
hill and decide I just cannot do it. What should
I do?
A:
Set the parking brake. If you have an automatic
transmission, shift to PARK (P). Turn off the
engine. Leave the vehicle and go get some help.
Exit on the uphill side and stay clear of the path the
vehicle would take if it rolled downhill. Do not
shift the transfer case to NEUTRAL when you leave
the vehicle. Leave it in some gear.
CAUTION:
{
Shifting the transfer case to NEUTRAL can
cause your vehicle to roll even if the
transmission is in PARK (P), or, if you have a
manual transmission, even if you are in gear.
4-30
CAUTION: (Continued)
CAUTION: (Continued)
This is because the NEUTRAL position on the
transfer case overrides the transmission. You
or someone else could be injured. If you are
going to leave your vehicle, set the parking
brake and shift the transmission to PARK (P),
or, put the manual transmission in FIRST (1).
But do not shift the transfer case to NEUTRAL.
Leave the transfer case in the Four-Wheel
High, Four-Wheel-High Lock, or
Four-Wheel-Low Lock position.