Jeep CJ 1945-1970 Repair Information

Automatic Transmission



The fluid level in automatic transmissions is checked with a dipstick in the filler pipe at the right rear of the engine. The fluid level should be maintained between the ADD and FULL marks on the end of the dipstick with the automatic transmission fluid at normal operating temperature. To raise the level from the ADD mark to the FULL mark, requires the addition of 1 pt. (0.473L) of fluid. The fluid level with the fluid at room temperature (75°F) should be approximately 1 / 4 in. (6mm) below the ADD mark.

In checking the Automatic Transmission Fluid (ATF), insert the dipstick in the filler tube with the markings toward the center of the vehicle. Also, remember that the FULL mark on the dipstick is calibrated for normal operating temperature. This temperature is obtained only after at least 15 miles (24 km) of expressway driving or the equivalent of city driving.

  1. With the transmission in Park, the engine running at idle speed, the foot brake applied and the vehicle resting on level ground, move the transmission gear selector through each of the gear positions, including Reverse, allowing time for the transmission to engage. Return the shift selector to the Park position and apply the parking brake. Do NOT turn the engine OFF , but leave it running at idle speed.
  3. Clean all dirt from around the transmission dipstick cap and the end of the filler tube.
  5. Pull the dipstick out of the tube, wipe it off with a clean cloth, and push it back into the tube all the way, making sure that it seats completely.
  7. Pull the dipstick out of the tube again and read the level of the fluid on the stick. The level should be between the ADD and FULL marks. If fluid must be added, add enough fluid through the tube to raise the level to between the ADD and FULL marks. Do not overfill the transmission because this will cause foaming and loss of fluid through the vent.

Use only Dexron® or Dexron®II transmission fluid.


See Figures 1, 2, 3, 4 and 5

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Fig. Fig. 1: On automatic transmissions without drain plugs, loosen the pan bolts and allow one corner of the pan to hang so that the fluid will drain out

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Fig. Fig. 2: Once the pan is removed, the filter can be replaced with a new one

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Fig. Fig. 3: Clean the fluid pan thoroughly with a safe solvent and allow it to air dry

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Fig. Fig. 4: Install a new pan-to-transmission housing gasket onto the fluid pan and install the pan

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Fig. Fig. 5: Fill the transmission with the proper amount of fluid-do NOT overfill the transmission

If, when the ATF level is checked, the fluid is noticed to be discolored from a clear red to brown, has a burned smell, or contains water, it should be changed immediately.

  1. Drive the vehicle for at least 20 minutes at expressway speeds or the equivalent to raise the temperature of the fluid to its normal operating range.
  3. Drain the ATF into an appropriate container before it has cooled. The fluid is drained by loosening the transmission pan and allowing the fluid to run out around the edges. It is best to loosen only one corner of the pan and allow most of the fluid to drain out.
  5. Remove the remaining pan screws, and remove the pan and pan gasket.
  7. Remove the strainer and discard it.
  9. Remove the O-ring seal from the pick-up pipe and discard it.
  11. Install a new O-ring seal on the pick-up pipe and install the new strainer and pipe assembly.
  13. Thoroughly clean the bottom pan and position a new gasket on the pan mating surface.
  15. Install the pan and tighten the attaching screws to 121-158 inch lbs. (14-18 Nm).
  17. Pour about 5 qts. (4.74L) of Dexron® or Dexron®II ATF down the dipstick tube. Make sure that the funnel, container, hose or any other item used to assist in filling the transmission is clean.
  19. Start the engine with the transmission in Park. Do NOT race it. Allow the engine to idle for a few minutes.
  21. After the engine has been running for a few minutes, move the selector lever through all of the gears.
  23. With the selector lever in Park, check the transmission fluid level and adjust as necessary. Remember the ATF must be warm when at the Full mark.