Hummer 2006 H2 Owner's Manual page 107

The transfer case is a part of the Full-Time Four-Wheel
Drive system and allows the following four different
modes of operation:
m
4 (Full-Time Four-Wheel Drive): This setting is
used for driving in most street and highway situations.
You can also use this setting for light or variable
off-road conditions.
m Q
4 (Four-Wheel-High Lock): Use this mode
when you need extra traction in most off-road situations
such as sand, mud, snow, or level, rocky trails.
n Q
4 (Four-Wheel-Low Lock): This mode delivers
extra torque to all four wheels and is used for extreme
off-road conditions. You might choose
Four-Wheel-Low Lock if you are driving off-road in deep
sand, mud, or snow and climbing or descending
steep hills.
When in this mode you can also choose to lock the rear
axle for additional traction in extreme off-road situations.
See Locking Rear Axle on page 4-10.
Notice: Operating your vehicle in
Four-Wheel-Low Lock above 50 mph (80 km/h) for
any extended period of time could cause damage to
the transfer case. Do not operate your vehicle in
Four-Wheel-Low Lock above 50 mph (80 km/h) for
extended periods.
CAUTION:
{
Shifting the transfer case to NEUTRAL can
cause your vehicle to roll even if the
transmission is in PARK (P). You or someone
else could be seriously injured. Be sure to set
the parking brake before placing the transfer
case in NEUTRAL. See Parking Brake on
page 2-34.
N (NEUTRAL): Shift the vehicle's transfer case to
NEUTRAL only when towing your vehicle. See
Recreational Vehicle Towing on page 4-60 or Towing
Your Vehicle on page 4-59 for more information.
2-31