FORD 2011 F-550 v.4 - Manual (Page 303)

Note: Some noise may be heard as the system shifts or engages; this is
normal.
Note: 4x4 low mode is not intended for use on dry pavement.
Driving off-road with truck and utility vehicles
4WD vehicles are specially equipped for driving on sand, snow, mud and
rough terrain and have operating characteristics that are somewhat
different from conventional vehicles, both on and off the road.
Your vehicle may be equipped with a long front air dam that may become
damaged (due to reduced ground clearance) when taking your vehicle
off-road. This air dam can either be removed or a shorter air dam can be
purchased from your authorized dealer. In either case, if the air dam is
to be removed (or replaced) before going off-road, refer to the
Workshop Manual for the procedure or have your authorized dealer
perform the work for you.
How your vehicle differs from other vehicles
Truck and utility vehicles can differ from some other vehicles. Your
vehicle may be higher to allow it to travel over rough terrain without
getting hung up or damaging underbody components.
The differences that make your vehicle so versatile also make it handle
differently than an ordinary passenger car.
Maintain steering wheel control at all times, especially in rough terrain.
Since sudden changes in terrain can result in abrupt steering wheel
motion, make sure you grip the steering wheel from the outside. Do not
grip the spokes.
Drive cautiously to avoid vehicle damage from concealed objects such as
rocks and stumps.
You should either know the terrain or examine maps of the area before
driving. Map out your route before driving in the area. To maintain
steering and braking control of your vehicle, you must have all four
wheels on the ground and they must be rolling, not sliding or spinning.
Basic operating principles
• Do not use 4WD on dry, hard surfaced roads. Doing so will produce
excessive noise, increase tire wear and may damage drive components.
4WD modes are only intended for consistently slippery or loose
surfaces.
• Drive slower in strong crosswinds which can affect the normal steering
characteristics of your vehicle.
Driving
303
2011 F-250/350/450/550 (f23)
Owners Guide, 4th Printing
USA (fus)