GMC Sierra 2005, Owner'S Manual

Page: 114 / 570

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 5-119.
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
®
,
use PARK (P) for stationary operation of the Power
Takeoff (PTO), if equipped. The Allison Transmission
®
is 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.
{
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)
(Automatic Transmission) on page 2-51.
If you are pulling a trailer, see Towing a Trailer
on page 4-68.
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