Change Your Transmission Oil

If your transmission isn't shifting like it used to, it may be time to change the fluid. It should be changed at most every {{safesubst:#invoke:convert|convert}}, along with the filter, and gasket.


Automatic Transmissions

  1. Have your materials ready before propping up the car.
  2. Drive the vehicle until it's at normal operating temperature. This allows any built-up sediment to be removed.
  3. Raise the car high enough to put it on jack stands.
    • Never get under a car supported only by jacks!
  4. Move all your tools under the car.
  5. Place the drain pan under the transmission oil pan and remove the oil pan bolts along the sides and rear edge of the pan.
  6. Loosen the front bolts, but don't remove them yet.
  7. Carefully pry the pan down starting at the rear, allowing the fluid to drain into the drain pan.
  8. If necessary, use a flathead screwdriver to break the gasket seal, but be careful not to damage the pan or surface of the transmission case in the process.
  9. Hold the pan with one hand, and use the other hand to remove the bolts at the front.
  10. Lower the pan and pour the rest of the fluid into the drain pan.
  11. Check the fluid and the bottom of the pan for metal particles that may indicate transmission failure.
  12. Mark the position of any magnets which may be present in the pan with a scriber.
  13. Clean the transmission oil pan and magnets (if present) with solvent and dry them well.
  14. Replace the magnets in the correct positions. Leave no lint in the pan.
  15. Be sure all remaining gasket material is gone. Use a gasket scraper or putty knife, but be careful not to damage the pan's mounting surface.
  16. Remove the bolts holding the transmission filter, and install the new filter.
  17. Apply a bead of gasket sealant around the transmission oil pan mounting surface, including between the bolt holes and the inner edge of the flange.
  18. Press the new gasket into place, making sure that all of the bolt holes line up.
  19. Lift the pan to the bottom of the transmission and insert the mounting bolts until they are finger-tight.
  20. Tighten the bolts with a torque wrench to the specified torque. Do not tighten them in order, rather, tighten them diagonally like lug nuts.
  21. Remove the jack stands and lower the vehicle.
  22. Raise the hood, and remove the transmission oil dipstick.
  23. Using a funnel, add a little fluid at a time, continually checking the level.
  24. Once the fluid just registers on the dipstick, start the engine, without using the accelerator.
  25. Let it run at a low idle for about two minutes, before pressing the brake pedal and shifting the transmission through each gear.
  26. Put the transmission back in park, and, with the engine still idling, check the fluid level on the dipstick.
  27. Check around the transmission oil pan for leaks.
  28. Add more fluid until the level on the dipstick is at the "cool" reading.
  29. Drive the vehicle until it's at normal operating temperature. Park on a level surface, and check the fluid level with the engine idling and the transmission in park.
  30. The fluid level should be to the top mark. If it's not, slowly add fluid to bring it up to this point.


  • Not all transmissions use a paper or metal gasket. There are also silicone sealed pans which will require you to reapply a silicone seal out of a tube.
  • It may not be necessary to remove the transmission pan. If you have a lot of miles or suspect you may find metal shavings, you should remove it.
  • Be certain to use fluid that is recommended by the vehicle manufacturer. Toyota and Honda vehicles require the use of automatic transmission oil available only at their parts departments.
  • Changing the automatic trans fluid should be done at 10,000-mile intervals. Remember, in most modern vehicles, less than half of the trans fluid will drain out. Most of the older fluid will be retained in the torque converter.
  • Check and double check that you have everything you need.
  • Every vehicle is different. Consider purchasing a Chilton's or Haynes guide for your specific vehicle.
  • Be careful when you buy oil. Make sure it's truly new oil.


  • Transmission fluid temperatures can exceed 350°F, so wear protective gloves and avoid contact with hot components.
  • Never reuse the old filter, or gasket. You're defeating the purpose.
  • Do not overfill your transmission.
  • Be sure to buy the proper transmission oil, filter and gasket for your car, before you begin. You won't be able to drive your car without transmission oil.
  • Never get under a car supported only by a jack. Always use jack stands or ramps.

Things You'll Need

  • Jack
  • Jack stands
  • Wrench
  • Torque wrench
  • Screwdriver
  • Pan to catch used transmission oil
  • Replacement transmission oil
  • Replacement filter
  • Replacement gaskets (or tube of silicone seal)
  • Gasket scraper or putty knife
  • Gasket sealant
  • Heat-resistant gloves
  • Solvent
  • Funnel

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