Ford recommends changing the automatic transmission fluid and filter in your 2001 Ranger every 30,000 miles. You should check your automatic transmission fluid every time you check your other fluids, to make sure it is at operating level. Additionally, check to see if the color is cherry red. If it is brown, there is probably a lot of clutch material mixed with the fluid and the filter should be changed right away. If the fluid has a burnt smell to it, you should have it inspected for any major problems at your local transmission shop.
Park your Ranger on a hard level surface, lift it using a floor jack and lower it onto jack stands. Make sure that the engine and transmission is cool.
Place the drain pan under the pan bolted to the bottom of the automatic transmission, remove all but the four corner pan bolts and then loosen the four remaining bolts. Fluid should start draining from the opposite corner of the pan, if not tap the side of the pan with your rubber mallet to break it loose. Wait for the fluid to stop draining, remove the four bolts left in the transmission pan and dump the fluid into the drain pan.
Remove the bolt holding the transmission filter to the valve body and pull the filter down to remove it. When you remove the filter, more fluid will drain out. Check the filter to see if the O-rings are on the tubes, if not, remove them from the valve body with your finger. Leave the drain pan under the transmission, because it will continue to drip fluid.
Remove the gasket from the pan. If your transmissions has a reusable rubber gasket, clean it and inspect it for damage. Clean and inspect the magnet and pan using a safe solvent, like brake cleaner. If the transmission had a cork gasket, remove any gasket material left on the pan and/or the transmission body, using a gasket scraper.
Lube and install the new o-rings on the filter. Push the tubes on the new filter into the valve body and secure the filter with its bolt, making sure the wire harness doesn't get pinched.
Place the gasket on the pan. If the old one was not reusable, try to get a quality rubber gasket to replace it. If you have no choice other than using a cork gasket, apply gasket sealer to prevent leaks.
Hold the transmission pan in place and thread the bolts in hand tight. Tighten the bolts starting with the middle bolts on each side and work your way out in a criss-cross pattern. Over tightening the pan bolts will cause a leak. Thread them down until they are flush against the pan and give them about a 1/4 turn more. Start back at the beginning to confirm that all of the bolts are tight.
Remove the jack stands and lower the truck to the ground.
Place your funnel in the transmission dipstick tube and pour about 3 1/2 quarts of transmission fluid in. Start the engine, set the parking brake, hold the brake pedal down and shift the selector through each position several times. Check the transmission fluid level and add as needed until it is in the safe zone. Add just a little at a time, and re-check the level. It is important not to overfill the transmission.
After the truck has warmed up, check the pan for leaks.
