VEHICLE CHARACTERISTICS
4WD and AWD Systems (if equipped)
A vehicle equipped with AWD or 4WD (when selected) has the ability to
use all four wheels to power itself. This increases traction which may
enable you to safely drive over terrain and road conditions that a
conventional two-wheel drive vehicle cannot.
Power is supplied to all four wheels through a transfer case or power
transfer unit. 4WD vehicles allow you to select different drive modes as
necessary. Information on transfer case operation and shifting procedures
can be found in theDrivingchapter. Information on transfer case
maintenance can be found in theMaintenance and Specifications
chapter. You should become thoroughly familiar with this information
before you operate your vehicle.
On some 4WD models, the initial shift from two-wheel drive to 4WD
while the vehicle is moving can cause a momentary clunk and ratcheting
sound. These sounds are normal as the front drivetrain comes up to
speed and is not cause for concern.
Do not become overconfident in the ability of 4WD and AWD
vehicles. Although a 4WD or AWD vehicle may accelerate better
than two-wheel drive vehicle in low traction situations, it won’t stop
any faster than two-wheel drive vehicles. Always drive at a safe speed.
2008 Expedition(exd)
Owners Guide (post-2002-fmt)
USA(fus)
Tires, Wheels and Loading
228
•Rear Wheel Drive (RWD)
vehicles/Four Wheel Drive
(4WD)/ All Wheel Drive (AWD)
vehicles (front tires at top of
diagram)
Sometimes irregular tire wear can be corrected by rotating the tires.
Note:If your tires show uneven wear ask an authorized dealer to check
for and correct any wheel misalignment, tire imbalance or mechanical
problem involved before tire rotation.
Note:Your vehicle may be equipped with a dissimilar spare tire/wheel. A
dissimilar spare tire/wheel is defined as a spare tire and/or wheel that is
different in brand, size or appearance from the road tires and wheels. If
you have a dissimilar spare tire/wheel it is intended for temporary use
only and should not be used in a tire rotation.
Note:After having your tires rotated, inflation pressure must be checked
and adjusted to the vehicle requirements.
INFORMATION CONTAINED ON THE TIRE SIDEWALL
Both U.S. and Canada Federal regulations require tire manufacturers to
place standardized information on the sidewall of all tires. This
information identifies and describes the fundamental characteristics of
the tire and also provides a U.S. DOT Tire Identification Number for
safety standard certification and in case of a recall.
2008 Expedition(exd)
Owners Guide (post-2002-fmt)
USA(fus)
Tires, Wheels and Loading
239
