FORD 2011 F-550 v.4 - Manual (Page 292)

If your vehicle gets stuck in mud or snow
If your vehicle gets stuck in mud or snow, it may be rocked out by
shifting between forward and reverse gears, stopping between shifts in a
steady pattern. Press lightly on the accelerator in each gear.
Do not rock the vehicle if the engine is not at normal operating
temperature or damage to the transmission may occur.
Do not rock the vehicle for more than a minute or damage to the
transmission and tires may occur, or the engine may overheat.
REVERSE SENSING SYSTEM (IF EQUIPPED)
The reverse sensing system (RSS) sounds a tone to warn the driver of
obstacles near the rear bumper when the R (Reverse) is selected and the
vehicle is moving at speeds less than 3 mph (5 km/h). The system is not
effective at speeds above 3 mph (5 km/h) and may not detect certain
angular or moving objects.
WARNING: To help avoid personal injury, please read and
understand the limitations of the reverse sensing system as
contained in this section. Reverse sensing is only an aid for some
(generally large and fixed) objects when moving in reverse on a flat
surface at “parking speeds”. Inclement weather may also affect the
function of the RSS; this may include reduced performance or a false
activation.
WARNING: To help avoid personal injury, always use caution
when in reverse and when using the RSS.
WARNING: This system is not designed to prevent contact with
small or moving objects. The system is designed to provide a
warning to assist the driver in detecting large stationary objects to
avoid damaging the vehicle. The system may not detect smaller
objects, particularly those close to the ground.
WARNING: Certain add-on devices such as large trailer hitches,
bike or surfboard racks and any device that may block the
normal detection zone of the RSS system may create false beeps.
Driving
292
2011 F-250/350/450/550 (f23)
Owners Guide, 4th Printing
USA (fus)