Transmission Filter


Before changing the transmission filter, review the recommended service intervals in the owner's manual and look at the vehicle's maintenance history.

Some transmissions have check balls, valves, and/or springs between the valve body and the filter or screen. Do not remove these. Pay special attention to these as you remove the filter. They can fall out and be lost.

  • Remove the filter and inspect it.
  • Filters are always replaced, whereas screens are cleaned.
  • Screens are removed in the same way as filters.
  • Clean a screen with fresh solvent and a stiff brush.
  • Make sure the O-ring for the filter was removed with the filter and not stuck on the housing.
  • Remove any traces of the old pan gasket on the case housing.
  • Then install a new filter and gasket on the bottom of the valve body and tighten the retaining bolts to the specified torque.

Make sure you check the specifications. The required torque is often given in inch-pounds. You can easily break the bolts or damage something if you tighten the bolts to foot-pounds.

  • Some transmissions are equipped with reusable oil pan and valve body gaskets.
  • Check with the service manual before you throw away the old gaskets.
  • Remove any traces of the old pan gasket from the oil pan.
  • Make sure the mounting flange of the oil pan is not distorted and bent.
  • Then re-install the pan using the sealant recommended by the manufacturer.
  • Pour a little less than the required amount of fluid into the transaxle through the dipstick tube.
  • Always use the recommended type of automatic transmission fluid (ATF).
  • Start the engine and allow it to idle for at least one minute.
  • Then, with the parking and service brakes applied, move the gear selector lever momentarily to each position, ending in park.
  • Recheck the fluid level and add a sufficient amount of fluid to bring the level to about 1/8 inch (3.0 mm) below the ADD mark.
  • Run the engine until it reaches normal operating temperature.
  • Then recheck the fluid level; it should be in the hot region on the dipstick.
  • Make sure the dipstick is fully seated into the dipstick tube opening. This will prevent dirt from entering into the transmission.

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