Drive Systems; Four-Wheel Drive - GMC Yukon XL 2015 Owner's Manual

9-36 Driving and Operating
The selector button is on the end of
the shift lever. Turn the Tow/Haul
Mode on and off by pressing the
button. When the Tow/Haul Mode is
enabled, a light on the instrument
cluster will come on.
See Tow/Haul Mode Light on
page 5-23 and Hill and Mountain
Roads on page 9-11.
Also see Tow/Haul Mode under
Towing Equipment on page 9-83.
Tow/Haul Mode Grade Braking
Tow/Haul Mode Grade Braking is
only enabled while the Tow/Haul
Mode is selected and the vehicle is
not in the Range Selection Mode.
See Tow/Haul Mode listed
previously and Manual Mode on
page 9-34. Tow/Haul Mode Grade
Braking assists in maintaining
desired vehicle speeds when driving
on downhill grades by using the
engine and transmission to slow the
vehicle.
On vehicles with a gasoline engine,
to disable or enable Tow/Haul
Grade Braking within the current
ignition key cycle, press and hold
the Tow/Haul button for
five seconds. When the button is
released, the requested mode
change is made. A DIC message is
displayed. See Transmission
Messages on page 5-40.
On vehicles with a diesel engine,
Tow/Haul Mode Grade Braking can
be enabled or disabled by pressing
the Tow/Haul Mode button. Use the
exhaust brake and Tow/Haul Mode
for maximum grade braking.
See Towing Equipment on
page 9-83.
For other forms of grade braking,
see Automatic Transmission on
page 9-31 and Cruise Control on
page 9-48.

Drive Systems

Four-Wheel Drive

If equipped, four-wheel drive
engages the front axle for extra
traction. Read the appropriate
section for transfer case operation
before using.
Caution
Driving on clean, dry pavement in
four-wheel drive for an extended
period of time may cause
premature wear on the system.
The damage would not be
covered by the vehicle warranty.
Driving on clean, dry pavement in
four-wheel drive may:
Cause a vibration to be felt in
the steering system.
Cause tires to wear faster.
Make the transfer case harder to
shift, and cause it to run noisier.