It's recommended that you change your CJ's transmission fluid every 100,000 miles. Be sure you have a secured and leveled area in which to work, with no distractions to take your attention away from your work and your safety. Because there is no drain plug through which you can easily empty the fluid, you'll need to get under your CJ and go through a detailed process.
Drive your CJ around for a minute to heat up the transmission fluid.
Raise your CJ onto four jack stands. The stands must hold the vehicle up by its frame rails.
Place your drain pan underneath the transmission. Remove the bolts from the rear and the two sides of the pan. Loosen, but don't remove, the front bolts.
Use your gasket splitter to break the seal between the pan and transmission casing on all sides. Let the pan hang down to drain.
Remove the front pan bolts and pour the remaining fluid into the drain pan.
Remove the bolted filter/strainer at the bottom of the transmission and the O-ring seal on the intake pipe.
Clean the pan with solvent. Wipe the pan clean, leaving no foreign matter.
Clean the filter/strainer's mounting surface. Place the new O-ring seal on the pipe and install the new filter/strainer.
Fit the new gasket onto the pan. Use petroleum jelly to keep the gasket in place.
Reinstall the pan to the transmission casing following a crisscross pattern with the bolts, for better fastening. Do not over-torque the bolts.
Bring your CJ down. Open the hood and remove the transmission fluid dipstick.
Use a funnel to add new transmission fluid. Start with about four quarts. Insert the dipstick, which should now read "Full."
Go inside the vehicle and apply the parking brake. While depressing the brake pedal, start your car. Let it idle for a few minutes.
Shift from gear to gear. Then shift back to park and shut the car off.
Check the dipstick again. Add more fluid until the fluid reaches the "Full" mark. Do not overfill or you may have to repeat the draining process to expel excess fluid.
Check all around your transmission area for leaks.
Drive the CJ until it has reached normal operating temperature, then check the dipstick again. It should still read "Full."
