GMC SIERRA 1997 Manual page 92

AUTOMATIC OVERDRIVE
(@): This position is for
normal driving. If you need more power for passing, and
you're:
Going less than about 35 mph (56
km/h),
push your
Going about 35 mph (56
km/h)
or more, push the
accelerator pedal about halfway down.
accelerator all the way down.
You'll shift down to the next gear and have more power.
AUTOMATIC OVERDRIVE
(a)
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.
THIRD (3): This position is also used for normal
driving, however it offers more power and lower fuel
economy than AUTOMATIC OVERDRIVE
( a ) .
SECOND (2): This position gives you more power but
lower fuel economy.
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)' the transmission will
drive in second gear. You may use this feature for reducing
torque to the rear wheels when you are trying
to
start
your
vehicle from a stop on slippery road surfaces.
FIRST (1): This position gives you even more power
(but lower fuel economy) than SECOND (2). You can
use it on very steep hills, or in deep snow or mud. If the
selector lever is put in FIRST (1) while the vehicle is
moving forward, the transmission won't shift into first
gear until the vehicle is going slowly enough.
NOTICE:
~ ~~
If your rear wheels can't rotate, don't try to
drive. This might happen if you were stuck in
very deep sand or mud or were up against a solid
object. You could damage your transmission.
Also, if you stop when going uphill, don't hold
your vehicle there with only the accelerator
pedal. This could overheat and damage the
transmission. Use your brakes or shift into
PARK (P) to hold your vehicle in position
on a hill.
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