GMC TopKick 2007 Owner's Manual page 122

Shifting Into NEUTRAL
Before shifting the transfer case to NEUTRAL, first
make sure the vehicle is parked so that it will
not roll.
1. Set the parking brake.
2. Start the vehicle.
3. Put the transmission in NEUTRAL (N).
4. Shift the transfer case to Two-Wheel High.
5. Turn the transfer case knob all of the way past
Four-Wheel Low and hold it there for a
minimum of 10 seconds. The NEUTRAL
indicator light comes on.
6. Shift the transmission to REVERSE (R) for
one second, then shift the transmission to
DRIVE (D) for one second.
7. Turn the ignition to OFF.
8. Place the transmission shift lever in PARK. (P).
9. Turn the ignition to LOCK.
122
Shifting Out of NEUTRAL
To shift the transfer case out of NEUTRAL, do the
following:
1. Set the parking brake and apply the regular
brake pedal.
2. Turn the ignition to RUN with the engine off.
3. Put the transmission in NEUTRAL (N).
4. Turn the transfer case knob to the desired
shift position (Two-Wheel High, Four-Wheel
High, Four-Wheel Low).
5. After the transfer case has shifted out of
NEUTRAL, the indicator light goes out.
Notice: Driving with the parking brake on can
overheat the brake system and cause
premature wear or damage to brake system
parts. Verify that the parking brake is fully
released and the brake warning light is
off before driving.
6. Release the parking brake.
7. Start the engine and shift the transmission
lever to the desired position.