GMC 1999 Suburban Owner's Manual page 88

AUTOMATIC OVERDRIVE (
normal driving. If you need more power for passing,
and you're:
D
Going less than about 35 mph (56 km/h), push your
accelerator pedal about halfway down.
D
Going about 35 mph (56 km/h) or more, push the
accelerator all the way down.
You'll shift down to the next gear and have
more power.
AUTOMATIC OVERDRIVE (
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 (
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.
2-18
B
): This position is for
B
) can be used when
B
).
If your vehicle is under 8600 lbs. GVWR, when 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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