FORD 2003 E-550 v.1 - Manual (Page 160)

WRECKER TOWING
For towing, contact a professional towing service or your roadside
assistance center.
Ford recommends your vehicle be towed with a wheel lift or flatbed. Do
not tow with a slingbelt. Ford Motor Company has not approved a
slingbelt towing procedure.
If your vehicle is equipped with an air dam and must be towed from the
front, it is recommended that your vehicle be towed by wheel lift or
flatbed equipment to prevent damage to the air dam.
If the vehicle is towed by other means or incorrectly, vehicle
damage may occur.
Roadside Emergencies
160