GMC Sierra Classic 2007 Owner's Manual page 140

To rock your vehicle back and forth to get out of
snow, ice, or sand without damaging your
transmission, see If Your Vehicle is Stuck in Sand,
Mud, Ice, or Snow on page 400.
NEUTRAL (N): In this position, your engine does
not connect with the wheels. To restart when
you are already moving, use NEUTRAL (N) only.
Also, use NEUTRAL (N) when your vehicle is
being towed.
CAUTION:
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Shifting into a drive gear while your
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.
140
Notice: Shifting out of PARK (P) or
NEUTRAL (N) with the engine running at high
speed may damage the transmission. The
repairs would not be covered by your warranty.
Be sure the engine is not running at high
speed when shifting your vehicle.
DRIVE (D): This position is for normal driving. It
provides the best fuel economy for your vehicle. If
you need more power for passing, and you are:
•
Going less than about 35 mph (55 km/h),
push your accelerator pedal about
halfway down.
•
Going about 35 mph (55 km/h) or more, push
the accelerator all the way down.
By doing this, the vehicle shifts down to the
next gear and has more power.
Downshifting the transmission in slippery road
conditions could result in skidding, see "Skidding"
under Loss of Control on page 365
DRIVE (D) can be used when towing a trailer,
carrying a heavy load, driving on steep hills, or for
off-road driving. You may want to shift the
transmission to THIRD (3) or, if necessary, a lower
gear selection if the transmission shifts too often.