GMC 2006 Yukon XL Owner's Manual page 126

Shifting into NEUTRAL
To shift the transfer case to NEUTRAL do the following:
1. Make sure the vehicle is parked so that it will
not roll.
2. Set the parking brake. See Parking Brake on
page 2-31 for more information.
3. Start the vehicle or turn the ignition to RUN.
4. Put the transmission in NEUTRAL (N).
5. Shift the transfer case to Two-Wheel High.
6. Simultaneously press and hold the Two-Wheel High
and Four-Wheel Low buttons for 10 seconds.
The NEUTRAL light will come on when the transfer
case shift to NEUTRAL is complete.
7. If the engine is running, verify that the transmission
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 ACCESSORY, which will turn
the engine off.
9. Place the transmission shift lever in PARK (P).
10. Turn the ignition to LOCK.
2-30
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. Press the button for the desired transfer case
shift position (Two-Wheel High, Four-Wheel High,
AUTO 4WD, or Four-Wheel Low).
After the transfer case has shifted out of
NEUTRAL the NEUTRAL light will go out.
4. Release the parking brake.
Notice: Shifting the transmission into gear
before the Four-Wheel Low indicator light has
stopped flashing could damage the transfer case.
To help avoid damaging your vehicle, always
wait for the Four-Wheel Low indicator light 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.