Chevrolet Silverado 2007 Owner's Manual page 149

If the shift stabilization feature determines that a
current vehicle speed cannot be maintained,
the transmission does not upshift and instead
holds the current gear. In some cases, this could
appear to be a delayed shift, however the
transmission is operating normally.
Your vehicle's transmission uses adaptive shift
controls. Adaptive shift controls continually
compares key shift parameters to pre-programmed
ideal shifts stored in the transmissions computer.
The transmission constantly makes adjustments to
improve vehicle performance according to how the
vehicle is being used, such as with a heavy load or
when temperature changes. During this adaptive
shift control process, shifting might feel different as
the transmission determines the best settings.
When temperatures are very cold, the Allison
®
Transmission and Hydra-Matic
transmission's gear shifting could be delayed
providing more stable shifts until the engine warms
up. Shifts could be more noticeable with a cold
transmission. This difference in shifting is normal.
MANUAL MODE (M): This position, is available
on vehicles with the Allison Transmission
®
Hydra-Matic 6-Speed transmission. It lets drivers
®
6-Speed
®
or
select the range of gears appropriate for current
driving conditions. If your vehicle has this feature,
see Range Select Mode (Allison Transmission
®
Hydra-Matic 6-Speed transmission) later in this
section.
THIRD (3): This position is also used for normal
driving. It reduces vehicle speed more than
DRIVE (D) without using the 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 the 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.
®
or
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