GMC 2001 Sierra 1500 Pickup Owner's Manual page 128

D
Move the lever up as far as it will go.
3. Be sure the transfer case is in a drive gear
in NEUTRAL (N).
4. Turn the ignition key to LOCK.
5. Remove the key and take it with you. If you can
leave your vehicle with the ignition key in your
hand, your vehicle is in PARK (P).
Leaving Your Vehicle With the Engine
Running (Automatic Transmission Only)
CAUTION:
It can be dangerous to leave your vehicle with
the engine running. Your vehicle could move
suddenly if the shift lever is not fully in PARK (P)
with the parking brake firmly set. If you have
-
four wheel drive with a manual transfer
case shift lever and your transfer case is in
NEUTRAL, your vehicle will be free to roll,
even if your shift lever is in PARK (P). So be
sure the transfer case is in a drive gear
--
not
NEUTRAL. And, if you leave the vehicle with the
engine running, it could overheat and even catch
fire. You or others could be injured. Don't leave
your vehicle with the engine running unless
you have to.
--
not in
2-45