GMC 2006 Sierra 1500 Pickup Owner's Manual page 136

Automatic Transfer Case
Use these switches to shift into and out of
four-wheel drive.
2-42
The transfer case buttons
are located to the left of the
instrument panel cluster.
Recommended Transfer Case Settings
Driving
Conditions
m
2
Normal YES
Variable
Severe
Extreme
Vehicle in
Tow*
*See Recreational Vehicle Towing on page 4-62 for
further information.
You can choose among four driving settings:
Notice: Driving on clean, dry pavement in
Four-Wheel-Drive High or Four-Wheel-Drive Low for
an extended period of time may cause premature
wear on your vehicle's powertrain. Do not drive on
clean, dry pavement in Four-Wheel Drive High or
Four-Wheel-Drive Low for extended periods of time.
AUTO 4WD (Automatic Four-Wheel Drive): This
setting is ideal for use when road surface traction
conditions are variable. When driving your vehicle in
Automatic Four-Wheel Drive, the front axle is engaged,
but the vehicle's power is sent to the rear wheels.
Transfer Case Settings
AUTO
m n
4 4
4WD
YES
YES
YES
N
YES