Jeep CJ/Scrambler 1971-1986 Repair Guide

Automatic Transmission


See Figures 1, 2 and 3


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 temperatures. To raise the level from the ADD mark to the FULL mark, requires the addition of one pint of fluid. The fluid level with the fluid at room temperature (75°F [24°C]) should be approximately 1 / 4 in. below the ADD mark.

In checking the automatic transmission fluid, 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 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®II transmission fluid.


If, when the transmission fluid 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 automatic transmission fluid 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 pickup pipe and discard it.
  11. Install a new O-ring seal on the pickup 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 10-13 ft. lbs.
  17. Pour about 5 qts. of Dexron®II automatic transmission fluid 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 transmission fluid must be warm when at the Full mark.

On some 1977-79 models, fluid may overflow through the filler pipe, or vent tube. If this condition occurs:

  1. Insert a length of stiff wire into the vent tube. If the tube is restricted, clean of replace it.
  3. If the tube is not restricted, make sure that the fluid level is correct. If the fluid level is correct perform a road test. If the fluid overflows during the road test.
  5. Raise and support the vehicle on jackstands.
  7. Loosen the vacuum modulator adapter retaining bolt. Pull the modulator outward about 1 / 2 -1 in. (13-25mm). Drain off about 1 pint of fluid. Seat the modulator and tighten the attaching bolt. Lower the vehicle and road test. Check the fluid level and file a new mark on the dipstick for the new fill level.

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Fig. Fig. 1: Many automatic transmissions have no drain plug. Loosen the pan bolts and allow the fluid to drain from one corner of the pan

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Fig. Fig. 2: Remove the automatic transmission filter, by removing the retaining bolts

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Fig. Fig. 3: Install a new fluid pan gasket, before installing the transmission pan