FORD 2013 Expedition v.3 - Manual (Page 334)

A vehicle equipped with four-wheel drive (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. Four-wheel drive vehicles allow you to select different drive
modes as necessary. You can find information on transfer case operation
and shifting procedures in the Transmission chapter. You can find
information on transfer case maintenance in the Maintenance chapter.
You should become thoroughly familiar with this information before you
operate your vehicle.
On some four-wheel drive models, the initial shift from two-wheel drive
to four-wheel drive 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 are not cause for concern.
How Your Vehicle Differs from Other Vehicles
Sport-utility vehicles, vans and
trucks can differ from some other
vehicles in a few noticeable ways.
Your vehicle may be:
• Higher – to allow higher load
carrying capacity and to allow it
to travel over rough terrain
without getting hung up or
damaging underbody
components.
• Shorter – to give it the capability
to approach inclines and drive
over the crest of a hill without
getting hung up or damaging
underbody components. All other
things held equal, a shorter
wheelbase may make your vehicle
quicker to respond to steering
inputs than a vehicle with a
longer wheelbase.
Wheels and Tires 333
2013 Expedition (exd)
Owners Guide gf, 3rd Printing, April 2013
USA (fus)