FORD 2002 F-550 v.3 - Manual (Page 218)

WRECKER TOWING
If you need to have your vehicle towed, contact a professional towing
service or, if you are a member, your roadside assistance center.
On 4x2 vehicles, it is acceptable to tow the vehicle with the front wheels
on the ground and the rear wheels off the ground using a wheel lift or a
slingbelt with T-hooks.
On 4x4 vehicles, it is recommended that your vehicle be towed with a
wheel lift or flatbed equipment with all the wheels off the ground.
However, a slingbelt with T-hooks and a wheel dolly can also be used if
all four wheels are off the ground.
Roadside Emergencies
218