GMC 2011 Yukon XL Denali Owner's Manual page 294

9-36 Driving and Operating
D (Drive): This position is for
normal driving. It provides the best
fuel economy for the vehicle. If you
need more power for passing, and
you are:
Going less than about 55 km/h
(35 mph), push the accelerator
pedal about halfway down.
Going about 55 km/h (35 mph) or
more, push the accelerator all
the way down.
D (Drive) 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 a lower gear
selection if the transmission shifts
too often.
Downshifting the transmission in
slippery road conditions could result
in skidding, see Skidding under
Loss of Control on page 9 6.
When temperatures are very cold,
®
the Hydra-Matic automatic
transmission's gear shifting may be
delayed providing more stable shifts
until the engine warms up. Shifts
may be more noticeable with a cold
transmission. This difference in
shifting is normal.
M (Manual Mode): This position
lets drivers select the range of gears
appropriate for current driving
conditions. See Range Selection
Mode under Manual Mode on
page 9 37.
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 the vehicle
warranty. If you are stuck, do not
spin the tires. When stopping on
a hill, use the brakes to hold the
vehicle in place.
The vehicle has a shift stabilization
feature that adjusts the transmission
shifting to the current driving
conditions in order to reduce rapid
upshifts and downshifts. This shift
stabilization feature is designed to
determine, before making an
upshift, if the engine will be able to
maintain vehicle speed by analyzing
things such as throttle position,
vehicle load, and hill grade. 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
may appear to be a delayed shift,
however the transmission is
operating normally.
The vehicle's transmission uses
adaptive shift controls. Adaptive
shift controls continually compares
key shift parameters to pre
programmed ideal shift conditions
stored in the transmissions
computer. The transmission
constantly makes adjustments to
improve vehicle performance
according to the way the vehicle is
being used, such as with a heavy
load. During this adaptive shift
controls process, some shifts may
feel different as the transmission
determines the best settings for a
particular shift.