GMC Sierra Classic 2007 Owner's Manual page 142

THIRD (3): This position is also used for normal
driving. However, it reduces vehicle speed
more than DRIVE (D) without using your brakes.
You might choose THIRD (3) instead of DRIVE (D)
when driving on hilly, winding roads, when
towing a trailer, so there is less shifting between
gears and when going down a steep hill.
SECOND (2): This position reduces vehicle speed
even more than THIRD (3) without using your
brakes. You can use SECOND (2) on hills. It can
help control your speed as you go down steep
mountain roads, but then you would also want to
use your brakes off and on.
If you manually select SECOND (2) in an
automatic transmission, the transmission will start
in second gear. You can use this feature for
reducing the speed of the rear wheels when you
are trying to start your vehicle from a stop on
slippery road surfaces.
For an Allison Transmission
Mode later in this section.
142
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, see Low Traction
FIRST (1): For an automatic transmission, this
position reduces vehicle speed even more
than SECOND (2) without using your brakes. You
can use it on very steep hills, or in deep snow
or mud. If the shift lever is put in FIRST (1) while
the vehicle is moving forward, the transmission
will not shift into first gear until the vehicle is going
slowly enough.
For an Allison Transmission
reduces vehicle speed, without using your brakes.
You can use it for major/sever downgrades and
off-road driving where the vehicle would otherwise
accelerate due to steepness of grade. When
you shift to FIRST (1) it will provide the lowest gear
appropriate to your current road speed and will
continue to downshift as the vehicle slows,
eventually downshifting to FIRST (1) gear.
Notice: Spinning the tires or holding
the vehicle in one place on a hill using
only the accelerator pedal may damage the
transmission. The repair will not be covered by
your warranty. If you are stuck, do not spin the
tires. When stopping on a hill, use the brakes to
hold the vehicle in place.
®
, This position