GMC 2012 Sierra Series Owner's Manual page 340

9-56 Driving and Operating
5. Shift the transfer case to
Two-Wheel Drive High.
6. Turn the transfer case dial
clockwise to N (Neutral) until it
stops and hold it there until the
N (Neutral) light starts blinking.
This will take at least
10 seconds. Then slowly release
the dial to the four low position.
The N (Neutral) light will come
on when the transfer case shift
to N (Neutral) is complete.
7. If the engine is running, make
sure that the transfer case is in
N (Neutral) by shifting the
transmission to R (Reverse) for
one second, then shift the
transmission to D (Drive) for
one second.
8. Turn the ignition to ACC/
ACCESSORY, which will turn the
engine off.
9. Place the transmission shift
lever in P (Park).
10. Release the parking brake prior
to moving the vehicle.
11. Turn the ignition to LOCK/OFF.
Shifting Out of Neutral
To shift out of N (Neutral) do the
following:
1. Set the parking brake and apply
the regular brake pedal.
2. Turn the ignition to ON/RUN with
the engine off, and shift the
transmission to N (Neutral).
3. Turn the transfer case dial to
Two-Wheel Drive High,
Four-Wheel Drive High,
or AUTO.
After the transfer case has
shifted out of N (Neutral), the
N (Neutral) light will go out.
I n f o r ma t i o n P r o v i d e d b y :
4. Release the parking brake prior
to moving the vehicle.
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.
5. Start the engine and shift the
transmission to the desired
position.