Hummer 2008 H2 Owner's Manual page 121

Shifting Out of Four-Wheel Low Lock
To shift from Four-Wheel-Low Lock to Four-Wheel High
or Four-Wheel-High Lock, your vehicle must be
stopped or moving less than 3 mph (5 km/h) with the
transmission in NEUTRAL (N) and the ignition
in RUN. The preferred method for shifting out of
Four-Wheel-Low Lock is to have your vehicle moving
1 to 2 mph (1.6 to 3.2 km/h). Turn the dial to the
Four-Wheel High or Four-Wheel-High Lock position.
You must wait for the Four-Wheel High or
Four-Wheel-High Lock indicator light to stop flashing
and remain lit before shifting your transmission into gear.
It is normal for your vehicle to have engagement
noise and bump when shifting between Four-Wheel Low
and Four-Wheel High or Four-Wheel-High Lock ranges
or from NEUTRAL with the engine running.
If the Four-Wheel High or Four-Wheel-High Lock position
is selected when your vehicle is in gear and/or moving,
the Four-Wheel High or Four-Wheel-High Lock indicator
light will flash for 30 seconds but will not complete the
shift unless your vehicle is moving less than 3 mph
(5 km/h) and the transmission is in NEUTRAL (N).
Notice: Shifting the transmission into gear before
the indicator light stops flashing could cause
damage to the transfer case. Always wait until the
indicator light stops flashing before putting the
transmission back in gear.
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 and apply the regular brake
pedal. See Parking Brake on page 2-40
3. Start the vehicle or turn the ignition to ON/RUN.
4. Put the transmission in NEUTRAL (N).
5. Shift the transfer case to Two-Wheel Drive High.
6. Turn the transfer case dial clockwise to NEUTRAL
position. The transfer case will not shift to NEUTRAL
unless this position is held for 10 seconds.
The NEUTRAL light will come on and then the dial
can be slowly released. The dial will be in the
Four-Wheel Low Lock position but the transfer case
will be in NEUTRAL with the NEUTRAL light on.
7. If the engine is running, make sure 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.
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