Automatic Transmission Operation - GMC 2005 Sierra 1500 Pickup Owner's Manual

Automatic Transmission Operation

If your vehicle is equipped with an automatic
transmission, it features an electronic shift position
indicator within the instrument panel cluster. This display
must be powered anytime the shift lever is capable of
being moved out of PARK (P). See Fuses and
Circuit Breakers on page 5-122.
There are several different positions for your shift lever.
PARK (P): This position locks your rear wheels. It is
the best position to use when you start your engine
because your vehicle cannot move easily. If your vehicle
is equipped with the Allison Transmission
PARK (P) for stationary operation of the Power Takeoff
(PTO), if equipped. The Allison Transmission
equipped with park pawl designed to hold the higher
weight of commercial medium duty trucks. Therefore, the
®
Allison Transmission uses larger parts than other
automatic transmission. These larger parts may
sometimes make a clunk noise when the selector lever
is moved from DRIVE (D) or REVERSE (R) to
PARK (P). This is normal and there is no damage
occurring during these shifts.
2-26
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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
®
, use
you are on fairly level ground, always set your
parking brake and move the shift lever to
®
is
PARK (P). See Shifting Into Park (P) (Automatic
Transmission) on page 2-49. If you are pulling
a trailer, see Towing a Trailer on page 4-68.
CAUTION: