Automatic Transmission Operation - GMC T-Series 2007 Owner's Manual

Automatic Transmission Operation

GM builds vehicles with five and six-speed
automatic transmissions. This part of the
manual covers the basics of these. With
these transmissions, you will find an Allison
Transmission Operator's Manual in your vehicle
that goes into more detail. On the headliner, in
front of and above the driver, or in some other place
near the driver, you will see a label that describes
important operating facts about the automatic
transmission in your vehicle. Make sure you
follow the instructions on this label.
CAUTION:
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It can be dangerous to get out of your
vehicle without the parking brake firmly
set. Your vehicle can roll. 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 the parking brake.
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CAUTION:
{
Shifting into a drive gear while the 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.
Overdrive Defeat
If your vehicle has this feature, you can select to
limit the transmission to fourth gear. This may
be useful when operating at a higher Gross
Vehicle Weight (GVW) or where operating
conditions do not require fifth gear.