GMC 2004 Canyon Owner's Manual page 102

If you cannot shift out of PARK (P), ease pressure on
the shift lever by pushing the shift lever all the way into
PARK (P) as you maintain brake application. Then move
the shift lever into the gear you want. See Shifting
Out of Park (P) (Automatic Transmission) on page 2-32.
REVERSE (R): Use this gear to back up.
Notice: Shifting to REVERSE (R) while your vehicle
is moving forward could damage the transmission.
The repairs would not be covered by your warranty.
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 If You Are Stuck: In Sand, Mud, Ice or Snow on
page 4-44.
CAUTION:
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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.
So, be sure the transfer case is in a drive gear,
two-wheel high (2H) or four-wheel high (4H) or
four-wheel low (4L) — not in NEUTRAL.
See Shifting Into Park (P) on page 2-30.
2-22
NEUTRAL (N): In this position, your engine does not
connect with the wheels. To restart when you are
already moving, use NEUTRAL (N) only.
CAUTION:
{
Shifting into a drive gear while your engine is
running at high speed is dangerous. Unless
your foot is firmly on the brake pedal, your
vehicle could move very rapidly. You could
lose control and hit people or objects. Do not
shift into a drive gear while your engine is
running at high speed.
Notice: Shifting out of PARK (P) or NEUTRAL (N)
with the engine running at high speed may damage
the transmission. The repairs would not be covered
by your warranty. Be sure the engine is not running
at high speed when shifting your vehicle.