GMC 2016 Sierra Denali Owner's Manual page 205

204 Driving and Operating
power is sent to the front and rear
wheels automatically based on
driving conditions. This setting
provides slightly lower fuel economy
than 2 .
Do not use AUTO mode to park on
a steep grade with poor traction
such as ice, snow, mud or gravel. In
AUTO mode only the rear wheels
will hold the vehicle from sliding
when parked. If parking on a steep
grade, use 4 to keep all four
wheels engaged.
4 (Four-Wheel Drive High) : Use
this position when extra traction is
needed, such as when driving on
snowy or icy roads, off-roading,
or plowing snow.
4 (Four-Wheel Drive Low) : This
setting engages the front axle and
delivers extra torque. Choose 4
when driving off-road in deep sand,
deep mud, or deep snow, and while
climbing or descending steep hills.
Shifting into Four-Wheel Drive Low
will turn Traction Control and
StabiliTrak off. See Traction Control/
Electronic Stability Control 0 208.
Shifting Into 4 or AUTO
Turn the knob to the 4 or AUTO
position at any speed, except from 4
. The indicator light will flash while
shifting and will remain on when the
shift is completed.
Shifting Into 2
Turn the knob to 2 at any speed,
except when shifting from 4 . The
indicator light will flash while shifting
and will remain on when the shift is
completed.
Shifting Into 4
When 4 is engaged, keep vehicle
speed below 72 km/h (45 mph).
To shift to 4 :
1. 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). It is
best for the vehicle to be
moving 1.6 to 3.2 km/h
(1 to 2 mph).
2. Turn the knob to 4 . Wait for
the 4 indicator light to stop
flashing before shifting the
transmission into gear.
Caution
Shifting the transmission into gear
before the requested mode
indicator light has stopped
flashing could damage the
transfer case.
If the transmission is in gear and/or
moving more than 5 km/h (3 mph),
the 4 indicator light will flash for
30 seconds and not complete the
shift. After 30 seconds the transfer
case will shift to 4 . Turn the knob
to 4 to display the indicator. With
the vehicle moving less than 5 km/h
(3 mph), and the transmission in
N (Neutral), attempt the shift again.