GMC 2010 Sierra Owner's Manual page 191

Shifting into Neutral
To shift the transfer case to N (Neutral) do the following:
1. Make sure the vehicle is parked so that it will
not roll.
2. Set the parking brake and apply the regular brake
pedal. See Parking Brake on page 3 54 for more
information.
3. Shifting the transfer case into N (Neutral) can be
done with or without the engine running. Shifting
without the engine running should be done with the
ignition in ON/RUN.
4. Put the transmission in N (Neutral).
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.
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