Ford Super Duty Owner's Manual page 221

220 Four-Wheel Drive (If Equipped)
Driving on hilly or sloping terrain
Note: Avoid driving crosswise or turning on steep slopes or hills.
Although natural obstacles may make it necessary to travel diagonally up
or down a hill or steep incline, you should always try to drive straight up
or straight down. . A danger lies in losing traction, slipping sideways and
possibly rolling over. Whenever driving on a hill, determine beforehand
the route you will use. Do not drive over the crest of a hill without
seeing what conditions are on the other side. Do not drive in reverse
over a hill without the aid of an observer.
When climbing a steep slope or hill, start in a lower gear rather than
downshifting to a lower gear from a higher gear once the ascent has
started. This reduces strain on the engine and the possibility of stalling.
If you do stall out, do not try to turn around because you might roll over.
It is better to back down to a safe location.
Apply just enough power to the wheels to climb the hill. Too much
power will cause the tires to slip, spin or lose traction, resulting in loss
of vehicle control.
to steer. The front wheels have to be turning in order to steer the vehicle.
If your vehicle has anti-lock brakes, apply the brakes steadily. Do not
pump the brakes.
2013 F-250/350/450/550 (f23)
Owners Guide gf, 3rd Printing, December 2012
USA (fus)
Descend a hill in the same gear you
would use to climb up the hill to
avoid excessive brake application and
brake overheating. Do not descend in
neutral; instead, disengage overdrive
or manually shift to a lower gear.
When descending a steep hill, avoid
sudden hard braking as you could
lose control. When you brake hard,
the front wheels can't turn and if
they aren't turning, you won't be able