GMC Sierra 2008 Owner's Manual page 133

6. Turn the transfer case dial clockwise to NEUTRAL
till it stops and hold it for 10 seconds. Then
slowly release the dial to the four low position.
The NEUTRAL light will come on when the
transfer case shift to NEUTRAL is complete.
7. If the engine is running, verify that the transfer
case is in NEUTRAL (N) by shifting the transmission
to REVERSE (R) for one second, then shift the
transmission to DRIVE (D) for one second.
8. Turn the ignition to ACC/ACCESSORY, which will
turn the engine off.
9. Place the transmission shift lever in PARK (P).
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 NEUTRAL do the following:
1. Set the parking brake and apply the regular
brake pedal.
2. Shift the transmission to NEUTRAL (N) and
turn the ignition to RUN with the engine off.
3. Turn the transfer case dial to
Two-Wheel-Drive High.
After the transfer case has shifted out of
NEUTRAL the NEUTRAL light will go out.
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 your 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.
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.
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