1997 Ford Aerostar Owner's Manual - Page 194

If you are not certain that you are using the right equipment in the proper manner, see your Ford or Lincoln-Mercury dealer. Under certain circumstances, the trailer frontal area is not to exceed the base vehicle frontal area, no matter what size engine your vehicle has: u If you drive on roads with steep grades or on roads with moderate grades that are 5 miles (8 km) or longer. above 100˚F (38˚C). u If outside temperature in which you travel is Hitches For towing trailers up to 2,000 lb (907 kg), use a weight carrying hitch and ball which uniformly distributes the trailer tongue loads through the underbody structure. Use a frame-mounted weight distributing hitch for trailers over 2,000 lb (907 kg). Do not install a single or multi-clamp type bumper hitch, or a hitch which attaches to the axle. Underbody mounted hitches are acceptable if installed properly. Follow towing instructions of a reputable rental agency. Whenever a trailer hitch and hardware are removed, make sure all mounting holes in the underbody are properly sealed to prevent noxious gases or water from entering. Safety Chains Always use safety chains between your vehicle and trailer. Cross chains under the trailer tongue and allow slack for turning corners. Connect safety chains to the vehicle frame or hook retainers. Never attach chains to the bumper. 194