GMC YUKON XL 2003 Manual page 118

Automatic Transfer Case
The transfer case buttons
are located to the left of
the instrument panel
cluster.
Use these switches to shift into and out of four-wheel
drive.
You can choose among four driving settings:
(2HI): This setting is used for driving in most street
and highway situations. Your front axle is not engaged
in two-wheel drive. This setting also provides the
best fuel economy.
AUTO 4WD: This setting is ideal for use when road
conditions are variable. When driving your vehicle
in AUTO 4WD, the front axle is engaged, but the
vehicle's power is sent only to the rear wheels. When
the vehicle senses a ioss of traction, the system
will automatically engage four-wheel drive. Driving in
this mode results in slightly lower fuel economy
than 2HI.
(4HI): Use the 4HI position when you need extra
traction, such as on snowy or icy roads or in most
off-road situations. This setting also engages your front
axle to help drive your vehicle. This is the best setting
to use when plowing snow.
(4LO): This setting also engages your front axle
and delivers extra torque. You may never need
this setting. It sends maximum power to all four wheels.
You might choose 4LO if you are driving off-road in
deep sand, deep mud, deep snow and climbing
or descending steep hills.
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