GMC 2007 Sierra - Manual (Page 167)

Shifting from Four-Wheel Drive Low to
Four-Wheel Drive High or Two-Wheel
Drive High
To shift from Four-Wheel Drive Low to Four-Wheel
Drive High or Two-Wheel Drive High, your
vehicle must be stopped or moving less than
3 mph (5 km/h) with the transmission in
NEUTRAL (N) for an automatic transmission or
the clutch pedal pressed for a manual
transmission. The preferred method for shifting out
of Four-Wheel Drive Low is to have your vehicle
moving 3 mph (5 km/h).
Press and release the Two-Wheel Drive High or
Four-Wheel Drive High switch. You must wait
for the Two-Wheel Drive High or Four-Wheel Drive
High indicator light to stop flashing and stay on
before shifting the transmission into gear or
releasing the clutch pedal.
If the Four-Wheel Drive High switch is pressed
when your vehicle is in gear, the Four-Wheel Drive
High indicator light will flash for 30 seconds but
the vehicle will not complete the shift unless
it is moving slower than 3 mph (5 km/h) and the
transmission is in NEUTRAL (N).
Shifting into NEUTRAL
{ CAUTION:
Shifting the transfer case to NEUTRAL
can cause your vehicle to roll even if the
transmission is in PARK (P). You or
someone else could be seriously injured.
Be sure to set the parking brake before
placing the transfer case in NEUTRAL.
See Parking Brake on page 169.
To shift the transfer case to NEUTRAL, first make
sure the vehicle is parked so that it will not roll:
1. Set the parking brake and apply the regular
brake pedal.
2. Start the vehicle or turn the ignition to RUN.
3. Press the foot brake pedal and put the
transmission in NEUTRAL (N).
4. Shift the transfer case to Two-Wheel
Drive High.
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