FORD 2004 F-550 v.2 - Manual (Page 216)

WRECKER TOWING
If you need to have your vehicle towed, contact a professional towing
service or, if you are a member of a roadside assistance program, your
roadside assistance service provider.
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
flatbed equipment with all the wheels off the ground. However, a wheel
lift or slingbelt may be used in conjunction with a wheel dolly so that all
four wheels are off the ground.
2004 F250/350/450/550 (f23)
Owners Guide (post-2002-fmt)
USA English (fus)
Roadside Emergencies
216