GMC 2011 Sierra - Manual (Page 359)

Black plate (65,1) GMC Sierra Owner Manual - 2011
Driving and Operating 9-65
Shifting Into Two-Wheel
Drive High
Turn the knob to the Two-Wheel
Drive High position. This can be
done at any speed, except when
shifting from Four-Wheel Drive Low.
The indicator light will flash while
shifting. It will remain on when the
shift is completed.
Shifting Into Four-Wheel
Drive Low
When Four-Wheel Drive Low is
engaged, vehicle speed should
be kept below 72 km/h (45 mph).
Extended high-speed operation in
Four-Wheel Drive Low may damage
or shorten the life of the drivetrain.
To shift to the Four-Wheel Drive
Low position, the ignition must be
in ON/RUN and the vehicle must be
stopped or moving less than 5 km/h
(3 mph) with the transmission in
N (Neutral). The preferred method
for shifting into Four-Wheel Drive
Low is to have the vehicle moving
1.6 to 3.2 km/h (1 to 2 mph). Turn
the knob to the Four-Wheel Drive
Low position. You must wait for the
Four-Wheel Drive Low indicator
light to stop flashing and remain
on before shifting the transmission
into gear.
Notice: Shifting the transmission
into gear before the requested
mode indicator light has stopped
flashing could damage the
transfer case. To help avoid
damaging the vehicle, always
wait for the mode indicator lights
to stop flashing before shifting
the transmission into gear.
It is typical for the vehicle to
exhibit significant engagement
noise and bump when shifting
between Four-Wheel Drive Low
and Four-Wheel Drive High ranges
or from N (Neutral) with the engine
running.
If the knob is turned to the
Four-Wheel Drive Low position
when the vehicle is in gear and/or
moving, the Four-Wheel Drive
Low indicator light will flash for
30 seconds and not complete the
shift unless the vehicle is moving
less than 5 km/h (3 mph) and the
transmission is in N (Neutral).
After 30 seconds the transfer
case will shift to Four-Wheel
Drive High mode.