Ford Mercury Villager 1997 Owner's Manual page 238

Preparing to Tow
For your safety and for the good of your vehicle, use the right
equipment for the type of trailer you tow. Also, make sure that all
towing equipment is properly installed on your vehicle. If you
are not certain that you are using the right equipment in the proper
manner, see your dealer or a reliable trailer dealer.
Hitches
For towing trailers up to 2,000 lb. (907 kg), use a good
weight-carrying hitch and hitch ball which uniformly distributes
the trailer tongue load through the underbody structure.
For towing trailers up to 3,500 lb. (1,587 kg), use a frame-mounted
weight distributing hitch for trailers over 2,000 lb. (907 kg).
Do not use single clamp bumper hitches or hitches that attach to
the axle.
Whenever a trailer hitch and hardware are removed, make sure
all mounting holes in the underbody are properly sealed to prevent
exhaust fumes from entering the vehicle.
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.
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