Instructions:
Each make and model of car is different so it is important to locate all parts in the manual and determine their exact location before starting. Some vehicles also require special tools. Make sure your repair manual does not mention any special tools before you start.
What You Need:
Transmission Filter
Transmission gasket (Cork is cheaper but I don’t recommend. Neoprene is more durable and won’t break while you are putting it in)
Transmission sealer or weather stripping cement
Ratchet
Ratchet extension
Transmission Fluid
Liquid recycling containers
wheel barring grease
How to do it
Ensure that your car is parked on asphalt or gravel, not dirt or grass. Jack up your car, remove the dipstick, place an oil recycling container under the location of the plug and remove the transmission plug. This will drain out all of the fluid. If your transmission does not have a plug, simply loosen every other bolt that holds the pan on. As you loosen them, the fluid will begin to drain out around the pan. Keep loosening bolts until all except two are completely out. Push up on the pan with your hand and remove the last two remaining bolts.
Lower the pan down easy as it will be full of fluid that you need to inspect. Inside the pan you should see fluid, a few grayish flakes, but they should be very small dust particles. If you are changing the fluid in a ford, you may find a small plastic plug; this is fine and can be disposed of. It is used when they are making the transmission and you don’t need it. If you see any large pieces of metal or any chunks, you may have a problem and should call a mechanic right away.
Do not flush your transmission unless you can afford a new one. This procedure is very dangerous and there is a high chance that it could cause your transmission to strip.
Empty the fluid out of the pan. Gently clean around the edge of the pan to remove the old gasket. Do not damage the aluminum pan. Once the old gasket is removed, clean the pan well and allow it to dry.
Once the pan is dry, you can then pull out the new gasket. Use the weather-strip cement or gasket sealer to run around the edge of the pan. Make sure to place a strip right down the center of the edge and also around each of the holes where the bolt goes. Place the gasket around the edge of the pan. Gently lift up each portion and press it back down to ensure that there are no air bubbles in the cement. Place the pan upside down on a work bench or discrete spot in your drive way where it will not get damaged. Let the sealant dry completely. Only use this sealant on the pan side of the gasket, not on the transmission side. If you do, you will ruin your transmission pan.
Here is where it can get a bit tricky. Before you pull the filter, ensure that you make note of where the mounting bolts are at exactly. Not all of the bolts are the same so ensure that you know where each one goes. Next, you should match up the filter and make sure you have the right one. There may be a little bit of a difference, but the mounting bolt holes must match up. Using a plastic bag to cover the filter, remove the mounting bolts. The purpose of the plastic bag is that more fluid is behind the filter and this will help catch it, you can also use the bag for proper disposal of the filter.
Let your transmission drain for at least an hour to make sure that the gunk has time to run out. If your car has a plug on the torque converter, you should pull the plug on that as well, it holds quite a bit of transmission fluid, and we want to get the old fluid out.
After about an hour, place the plug back in the torque converter, and install the new filter the way the old one came out. Use wheel barring grease on the top of the pan gasket to allow for proper fit and easy removal. When putting the pan back up, tighten every other one until all of the bolts are tight. This ensures that there is not too much pressure in one spot at any time.
After you get the pan back on, put 2 quarts of transmission fluid in your car. Start your car and let it run until it reaches a normal temperature for running. Check your fluid. Add fluid until it is just below the full mark on your dipstick.
Get in your car, place your foot on the brake and move the car through the gears stopping at each gear. Do this 3 or 4 times all the way through the gears. Check the fluid level and ensure that it is still just below the full mark. If not, add a little more fluid until you get to this point.
Drive your car about 5 miles and check the fluid level again. Park your car in a spot other than where you changed your fluid to check for leaks. Where you changed it may have a few spots on the ground and you may not be able to tell.