The recommended automatic transmission fluid for this car varies between different year models, so check the owner's manual to confirm the fluid you should use. In addition, remember that the transmission maintenance schedule also varies among model years, so check the owner's manual for this as well. The following covers Mercury Cougar models from 1983 through 1997.
Raise and support the Cougar with jack stands. Place a drain pan under the transmission. Remove the fluid filler tube from the transmission fluid pan. Wait for the fluid to finish draining into the drain pan.
Remove the fluid pan retaining bolts, the pan and the gasket. You will need an appropriately sized socket wrench to remove the bolts. Try to drain the remaining fluid into the drain pan as carefully as possible.
Discard the old gasket, clean the fluid pan and the pan mating surfaces with a safe solvent. Set them aside to air dry. Unscrew the filter from the valve body, remove the filter and discard it. If your vehicle is equipped with a grommet, remove and discard it. Install a new filter and grommet (if equipped) onto the valve body.
Apply a new gasket onto the fluid pan, reinstall the fluid pan onto the transmission and tighten the retaining bolts to 10 to 16 ft-lb with a torque wrench. Return the Cougar to level ground.
Measure the amount of fluid that you drained from the transmission. Use a funnel to add the same amount of new transmission fluid to the transmission through the filler tube under the hood.
Start the engine and move the gear selector through the gears, ending in "Park." Let the engine idle for 10 to 15 minutes to reach normal operating temperature. Check the transmission fluid level and add more fluid if needed to bring the fluid level to the correct position on the dipstick. The fluid level should be between the "Full" and "Add" marks.
