GMC 2011 Sierra Owner's Manual page 353

The transfer case knob is located
next to the steering column.
Use the dial to shift into and out of
four-wheel drive.
Normal
Severe
Extreme
Vehicle in Tow*
*See
.
You can choose among four driving
settings:
Indicator lights in the dial
show which setting you are in.
The indicator lights will come on
briefly when you turn on the ignition
and one will stay on. If the lights do
not come on, you should take the
vehicle to your dealer for service.
An indicator light flashes while
shifting the transfer case and
YES
YES
YES
or
remains illuminated when the
shift is complete. If for some
reason the transfer case cannot
make a requested shift, it will return
to the last chosen setting.
setting is used for driving in most
street and highway situations.
The front axle is not engaged in
Two-Wheel Drive. This setting also
provides the best fuel economy.
YES
This