GMC Sierra Denali 2006, Owner'S Manual, Page: 87 / 438

Automatic Transmission Operation
Your vehicle is equipped with an automatic transmission
and features an electronic shift position indicator
located within the instrument panel cluster.
There are several different positions for your shift lever.
PARK (P): This position locks your drive wheels.
It is the best position to use when you start your engine
because your vehicle cannot move easily.
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CAUTION:
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.
Do not 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 will not move, even
when you are on fairly level ground, always set
your parking brake and move the shift lever to
PARK (P). See Shifting Into Park (P) on
page 2-24. If you are pulling a trailer, see
Towing a Trailer on page 4-49.
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