GMC SIERRA 1997 Manual page 90

If
your vehcle is equipped with an automatic transmission,
it now features
an electronic shift position indicator within
the instrument cluster. This display must be powered
anytime the shift lever is capable
of being moved out of
PARK (P). This means that if your key is in OFF, rather
than LOCK, there will be a small current drain on your
battery which could discharge your battery over
a period of time. If you have to leave your key in the
ignition in OFF for an extended period, it is recommended
that you disconnect the battery cable from the battery to
prevent discharging your battery.
PARK
(P):
This locks your rear wheels. It's the best
position to use when you start your engine because your
vehicle can't move easily.
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.
CAUTION: (Continued)
I
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 (2H) or four-wheel
high (4H) or four-wheel low (4L)
--
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.
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