GMC Envoy 2003 Owner's Manual page 95

Shifting into 4LO
To shift to 4LO, the vehicle's engine must be running
and the vehicle must be stopped or moving less
than 2 mph (3.2 km/h) with the transmission in
NEUTRAL (N). The preferred method for shifting into
4LO is to have your vehicle moving 1 or 2 mph (1.6 to
3.2 km/h). Turn the knob to 4LO. You must wait for
the 4LO indicator light to stop flashing and remain
illuminated before shifting your transmission into gear.
If you turn the knob to 4LO when your vehicle is in gear
and/or moving, the 4LO indicator light will flash for
30 seconds and not complete the shift unless your
vehicle is moving less than 2 mph (3.2 km/h) and the
transmission is in NEUTRAL (N). After 30 seconds, the
transfer case will return to the setting last chosen.
Shifting Out of 4LO
To shift from 4LO to 4HI, A4WD or 2HI your vehicle
must be stopped or moving less than 2 mph (3.2 km/h)
with the transmission in NEUTRAL (N) and the
engine running. The preferred method for shifting out of
4LO is to have your vehicle moving 1 or 2 mph (1.6
to 3.2 km/h). Turn the knob to 4HI, A4WD or 2HI. You
must wait for the 4HI, A4WD or 2HI indicator light to stop
flashing and remain illuminated before shifting your
transmission into gear.
If the knob is turned to 4HI, A4WD or 2HI when your
vehicle is in gear and/or moving, the 4HI, A4WD or 2HI
indicator light will flash for 30 seconds. It will not
complete the shift unless your vehicle is moving less
than 2 mph (3.2 km/h) with the transmission in
NEUTRAL (N).
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 2HI.
5. Turn the transfer case knob all of the way past 4LO
and hold it there for a minimum of 10 seconds. The
neutral indicator light will come on.
6. Shift the transmission to REVERSE (R) for one
second, then shift the transmission to DRIVE (D)
for one second.
7. Place the transmission shift lever in PARK (P).
8. Release the parking brake prior to towing.
9. Turn the ignition to LOCK.
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