Ford 1999 Explorer Owner's Manual page 199

Roadside emergencies
If equipped with air suspension, the air suspension control must be
turned to the OFF position.
The Ford approved towing procedure is flatbed or wheel lift with
dollies.
On 4x2 vehicles, it is acceptable to tow the vehicle with the front wheels
on the ground (without dollies) and the rear wheels off the ground.
On 4x4 vehicles, it is recommended that your vehicle be towed with a
wheel lift and dollies or flatbed equipment with all the wheels off the
ground.
If the vehicle is towed by other means or incorrectly, vehicle
damage may occur.
Do not tow with a slingbelt. Ford Motor Company has not approved a
slingbelt towing procedure.
A towing manual is available from Ford Motor Company for all authorized
tow truck operators. Have your tow truck driver refer to this manual for
proper hook-up and towing procedures for your vehicle.
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