FORD 2010 F-150 v.3 - Manual (Page 270)

In case of a roadside emergency with a disabled vehicle, see Wrecker
towing in the Roadside Emergencies chapter.
4WD vehicles equipped with an electronic-shift transfer case: Do
not tow your vehicle with any wheels on the ground, as vehicle or
transmission damage may occur. It is recommended to tow your vehicle
with all four (4) wheels off the ground such as when using a car-hauling
trailer. Otherwise, no recreational towing is permitted.
In case of a roadside emergency with a disabled vehicle, see Wrecker
towing in the Roadside Emergencies chapter.
Tires, Wheels and Loading
270
2010 F-150 (f12)
Owners Guide, 3rd Printing
USA (fus)