GMC 2011 Sierra Owner's Manual page 357

5. Start the engine and shift the
transmission to the desired
position.
Excessively shifting the transfer
case into or out of the different
modes may cause the transfer case
to enter the shift protection mode.
This will protect the transfer case
from possible damage and will only
allow the transfer case to respond
to one shift per 10 seconds.
The transfer case may stay in this
mode for up to three minutes.
The transfer case knob is located
next to the steering column.
Use the dial to shift into and out of
Four-Wheel Drive.
You can choose among five 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 will flash while
shifting the transfer case. It will
remain 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.
This