On most automatic transmissions with a serviceable filter, changing it means draining the fluid, removing the pan, pulling out the old filter and its seal, cleaning the pan and magnet, fitting a new filter, seal and pan gasket, and refilling with the correct fluid. The job usually replaces only part of the fluid, since much of it stays in the torque converter and cooler. Some modern transmissions have filters that are only replaced during an overhaul, so check the service information first.
How to change a transmission filter
- Warm the transmission briefly, then park level and support the vehicle safely.
- Drain the fluid through the drain plug, or loosen the pan bolts and let one corner drop to drain.
- Remove the pan and inspect the debris on the magnet and in the bottom.
- Pull the filter straight down. Check that the old filter seal came out with it; a seal left in the pump bore prevents the new one from sealing.
- Install the new filter and seal, clean the pan and magnet, and fit a new gasket.
- Tighten the pan bolts evenly to the specified torque, which is usually low; overtightening causes leaks.
- Refill with the specified fluid, start the engine, run through the gears and check the level by the correct procedure.
What the pan tells you
Fine gray paste on the magnet is normal wear. Metal chips, chunks of clutch material or a burnt smell point to internal damage that a filter change will not fix; see signs of a bad transmission.
Tools and parts
- The correct filter kit with seal and gasket for your transmission code
- The specified fluid, plus a little extra
- A large drain pan, a torque wrench that reads in inch-pounds, and a funnel with a long neck or a fluid pump
- Gasket scraper and lint-free rags
How often
Follow the service schedule. Many owners change the filter with every other fluid change, and more often when towing; see how often to change transmission fluid and transmission flush vs change.
Model notes
On GM 4L60E trucks the filter has a seal that often sticks in the pump; see 4L60E fluid capacity and type. Several newer six-, eight- and ten-speed units are filled through a check plug rather than a dipstick; see checking fluid without a dipstick.
After the change
Recheck for leaks after the first drive and recheck the level; see transmission pan gasket leak and how much transmission fluid do I need?
More guides: what the metal on the pan magnet means.
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