1996 Mercury Grand Marquis Owner's Manual - Page 197

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. When you tow down steep grades, move the gearshift to 1 (Low). It gives more engine braking to slow your vehicle than Drive on the downgrades. If you tow in D (Overdrive) while riding through hilly country, your vehicle may frequently shift between Overdrive and Third gears. To prevent your vehicle from shifting too much, press the Transmission Control Switch located on the shift lever. This will also give the engine more power going up hills and better engine braking going down hills. If you use the speed control while you are towing on very long, steep grades, the speed control may shut off. 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. 194