GMC 2009 Sierra 1500 Crew Cab Owner's Manual page 136

Some delay between shifting and when the indicator
light comes on is normal.
Recommended Transfer Case Settings
Driving Conditions
Normal
Severe
Extreme
Vehicle in Tow*
*See Recreational Vehicle Towing on page 4-47
Towing Your Vehicle on page 4-47
2-38
A Four-Wheel Drive
indicator light comes on
when you shift into
four-wheel drive and the
front axle engages.
See Four-Wheel-Drive
Light on page 3-51.
Transfer Case Settings
m m n
2 4 4
YES
YES
YES
Notice: Driving on clean, dry pavement in
four-wheel drive for an extended period of time can
cause premature wear on the vehicle's powertrain.
Do not drive on clean, dry pavement in Four-Wheel
Drive for extended periods of time.
n
4 (Four-Wheel-Drive Low): This setting also
engages the front axle and delivers extra torque.
You may never need Four-Wheel-Drive Low. It sends
maximum power to all four wheels. You might choose
Four-Wheel-Drive Low if you are driving off-road in deep
sand, deep mud, deep snow, and while climbing or
descending steep hills.
If the vehicle has StabiliTrak
Four-Wheel-Drive Low will turn Traction Control and
N
®
StabiliTrak off. See StabiliTrak
YES
®
, shifting into
®
System on page 4-6.