How to Flush Transmission Fluid

Lead Image
  • 2-4 hours
  • Intermediate
  • 35-50
What You'll Need
Car lift or ramps
Drain pan
Drill with wire wheel
New gasket
New transmission filter
Transmission fluid

One of the most important parts of car maintenance involves flushing out and replacing the transmission fluid. It is true a lot of people take their cars in to have their transmission flushed and new fluid put in. That does not have to be the case for you. If you want to save money, you can do it yourself relatively easy instead of taking it to a garage. Of course, you need to be willing to get a little dirty doing it.

Step 1 - Life the Car

Do not work on the vehicle if it is only being supported by a car jack. You should have the vehicle up on car ramps and on a flat surface.

Step 2 - Prepare the Transmission

Remove your transmission dip stick. A lot of transmissions have drain plugs, so you will need to locate this and then put your drain pan under that area of the transmission. If your transmission does not have a drain plug then make sure to place your drain pan directly under the transmission pan and begin removing every other transmission bolt.

Step 3 - Remove the Transmission Bolts

You will need to leave 2 of the transmission bolts on each side of the transmission but remove the rest of them and set aside. On one side, carefully remove the 2 bolts so the transmission fluid will begin to leak out. On the other side, begin to loosen the bolts very slowly. When it feels like the bolts are 2 or 3 threads from coming off, immediately push the transmission pan up and then remove the other 2 bolts and set aside as well. After all of the bolts are out, lower the pan and let the fluid flow into the drain pan.

Step 4 - Check for Debris

You should inspect the drain pan for debris. If there is a little bit of dust and small chunks it’s okay, but if there are large chunks of debris, you have a problem with your transmission.

Step 5 - Replace the Gasket

Use a drill with a wire wheel to remove the old transmission gasket. You can also use a scraper to remove the gasket as well. Transmission pans usually have a magnet that collects some of the metal dust. Make sure to clean the magnet off. Then clean off the transmission pan. After you have done that replace the magnet.

Step 6 - Remove the Transmission Filter

Make sure that the holes for mounting on the new filter match exactly to the old filter, otherwise the filter will not fit in your transmission. Do a visual check before proceeding. Remove the old filter by removing the mounting bolts. More fluid will probably come out when you are doing this so make sure the drain pan is in place. Remove the old filter and put it in a plastic bag that can be thrown away properly. After you have done this, get out from under the car and let the transmission drain for at least 1 hour before doing anything else to it.

Step 7 - Install a New Transmission Filter

After the transmission is drained you will now install the new filter. Put the drain plug back in. Grease the gasket with wheel bearing grease. Tighten the bolts for the transmission pan. Make sure that it is every other one that you tighten. Make sure not to tighten any more than 15 to 20 inch per pound. After the pan bolts are properly torqued, clean the area and lower the car.

Step 8 - Fill up and Finish

Put in 3 quarts of transmission fluid, and put the dip stick back in the vehicle. Check fluid level and add as needed.