Ford 1996 Aerostar Manual page 201

Driving while you tow
Be especially careful when driving while you
tow a trailer. Never drive faster than 45 mph
(70 km/h) when you tow in hilly country on
hot days. Also, anticipate stops so that you can
brake gradually.
If you use the speed control while you are
towing on very long, steep grades, the speed
control may shut off.
When towing a trailer in hilly terrain, with a
vehicle equipped with an automatic overdrive
transmission, you may wish to operate in Drive
(by cancelling Overdrive with OVERDRIVE OFF
button) rather than k (Overdrive). This will
eliminate excessive downshifting and upshifting
to maintain speed. Switch back to Overdrive
whenever practical for optimum powertrain
cooling. This can be accomplished by pushing in
the switch located on the end of the indicator
lever.
When descending a steep grade with a trailer,
operate in Drive rather than Overdrive. If
additional braking is needed, shift the automatic
transmission gearshift into 2 (Second) gear or 1
(Low).
Servicing your vehicle if you tow
If you tow a trailer for a long distance, your
vehicle will need to be serviced more frequently
than usual. Refer to the Maintenance Schedule and
Record booklet for additional information.
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