FORD 2003 Expedition v.1 - Manual (Page 214)

Power is supplied to all four wheels
through a transfer case. On
four–wheel drive vehicles, the
transfer case allows you to select
four–wheel drive when necessary.
Information on transfer case
operation and shifting procedures
can be found in this chapter.
Information on transfer case maintenance can be found in the
Maintenance and specifications chapter. You should become
thoroughly familiar with this information before you operate your vehicle.
Normal characteristics
On some four–wheel drive models, the initial shift from two-wheel drive
to four–wheel drive while the vehicle is moving can cause some
momentary clunk and ratcheting sounds. This is the front drivetrain
coming up to speed and engaging the front wheels, and is not cause for
concern.
Sand
When driving over sand, try to keep all four wheels on the most solid
area of the trail. Avoid reducing the tire pressures but shift to a lower
gear and drive steadily through the terrain. Apply the accelerator slowly
and avoid spinning the wheels.
If you must reduce the tire pressure for whatever reason in sand, make
sure you re-inflate the tires as soon as possible.
Avoid excessive speed because vehicle momentum can work against you
and cause the vehicle to become stuck to the point that assistance may
be required from another vehicle. Remember, you may be able to back
out the way you came if you proceed with caution.
If your vehicle is equipped with AdvanceTrac
௢, press the AdvanceTrac௢
button (refer to AdvanceTrac
௢ Stability Enhancement System in this
chapter) while driving in deep sand if you experience excessive engine
power reduction.
Driving
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