GMC 1996 Sonoma Owner's Manual page 63

It is dangerous to get out of your vehicle if the
shift lever
is
not fully in PARK
(P)
with the
parking brake firmly set. Your vehicle can roll.
Don't leave your vehicle when the engine is
running unless you have to. If you have left the
engine running, the vehicle can move suddenly.
You or others could be injured. To be sure your
vehicle won't move, even when you're on fairly
level ground, always set your parking brake and
move the shift lever to PARK (P).
If
you have four-wheel drive, your vehicle
will be free to roll
--
even if your shift lever
is in PARK (P)
--
if your transfer case is in
NEUTRAL
(N).
So, be sure the transfer case is in
a drive gear, two-wheel high (2HI) or four-wheel
high (4HI) or four-wheel low (4LO)
--
not in
NEUTRAL (N). See "Shifting Into PARK (P)" in
the Index. If you're pulling a trailer, see "Towing
a Trailer" in the Index.
Ensure the shift lever is fully in PARK (P) range
before starting the engine. Your vehicle has a
brake-transmission shift interlock. You have to fully
apply your regular brakes before you can shift from
PARK (P) when the ignition key is in the RUN position.
I f you cannot shift out of PARK (P), ease pressure on
the shift lever -- push the shift lever all the way into
PARK (P) as you maintain brake application. Then
move the shift lever into the gear you wish. See
"Shifting Out of PARK (P)" in the Index.
REVERSE (R): Use this gear to back up.
I
NOTICE:
I ~~~
Shifting to REVERSE (R) while your vehicle is
moving forward could damage your transmission.
Shift to REVERSE (R) only after your vehicle
is stopped.
To rock your vehicle back and forth
to
get out of snow,
ice or sand without damaging your transmission, see
"Stuck in Sand, Mud, Ice or Snow" in the Index.
2-15