1997 Ford Aerostar Owner's Manual - Page 245

5. If the power steering fluid is low, add fluid in small amounts, continuously checking the level, until you reach the FULL HOT range. Do not overfill. When you are finished, put the dipstick back in and make sure that it fits snugly. 6. Use only a power steering fluid such as Ford Power Steering Fluid Motorcraft MERCON ATF. If the power steering fluid is low, do not drive your vehicle for a long period of time before adding fluid. This can damage the power steering pump. If you check the power steering fluid when it is cold, make sure that the fluid reaches the FULL COLD range on the dipstick. The reading will only be accurate if the fluid temperature is approximately 50 to 85˚F (10 to 30˚C). NOTE: Do not turn the steering wheel of your vehicle with the engine off. It could force power steering fluid out from the reservoir cap or in extreme cases, it could unseat the cap. Automatic Transmission Fluid Under normal driving conditions automatic transmission fluid should be changed every 30,000 miles (48,000 km) or 21,000 miles (34,000 km) if under severe duty conditions. However, if the transmission is not working properly, for instance, the transmission may slip or shift slowly, or you may notice some sign of fluid leakage, the fluid level should be checked. It is preferable to check the transmission fluid level at normal operating temperature, after approximately 20 miles (30 km) of driving. However, if necessary, you can check the fluid 246