Yes and no. The rear band can be adjusted from the outside, but is a pain in the Ass. He may as well just pull the pan and adust them both from inside the tranny. Here's how, but you don't need to translate all of this. Since he will be adjusting the front and the rear at the same time, you can leave out all that stuff about putting the pan back on at the end of the front adjustment explanation.
And, if he really has an FMX and not a C4, he will need to use Dexron Fluid.
FRONT BAND ADJUSTMENT
When it is necessary to adjust the front band of the transmission, perform the following procedure:
Drain the transmission fluid and remove the oil pan, fluid filter screen, and clip. The same transmission fluid may be reused if it is filtered through a 100-mesh screen before being installed. Only transmission fluid in good condition should be used.
Clean the pan and filter screen and remove the old gasket.
Loosen the front servo adjusting screw locknut.
Special band adjusting wrenches are recommended to do this operation correctly and quickly.
Pull back the actuating rod and insert a 1/4 inch spacer bar between the adjusting screw and the servo piston stem. Tighten the adjusting screw to 10 inch lbs torque. Remove the spacer bar and tighten the adjusting screw an additional 3/4 turn. Hold the adjusting screw fast and tighten the locknut securely 20-25 ft. lbs.
Install the transmission fluid filter screen and clip. Install the pan with a new pan gasket.
Refill the transmission to the FULL mark on the dipstick. Start the engine, run for a few minutes, shift the selector lever through all positions, and place it in Park. Recheck the fluid level again and add fluid to the proper level if necessary.
REAR BAND ADJUSTMENT
The rear band of the FMX transmission may be adjusted by any of the methods given below. On most cars, the basic external band adjustment is satisfactory. The internal band adjustment procedure may be done when the external adjustment procedure cannot be done correctly. On certain cars with a console floor shift, the entire console, shift lever and linkage will have to be removed to gain access to the rear band external adjusting screw.
REAR BAND EXTERNAL ADJUSTMENT
The procedure for adjusting the rear band externally is as follows:
Locate the external rear band adjusting screw on the transmission case, clean all dirt from the threads, and coat the threads with light oil.
The adjusting screw is located on the upper right side of the transmission case. Access is often through a hole in the front floor to the right of center under the carpet.
Loosen the locknut on the rear band external adjusting screw.
Using the special preset torque wrench shown, tighten the adjusting screw until the handle clicks at 10 ft. lbs. If the adjusting screw is tighter than 10 ft. lbs., loosen the adjusting screw and retighten to the proper torque.
Back off the adjusting screw 11/2 turns. Hold the adjusting screw steady while tightening the locknut to the proper torque 35-40 ft. lbs. [cf2]Severe damage may result if the adjusting screw is not backed off exactly 11/2 turns.
REAR BAND INTERNAL ADJUSTMENT
The rear band is adjusted internally as follows:
Drain the transmission fluid. If it is to be reused, pour the fluid through a 100-mesh screen as it drains from the transmission. Reuse the transmission fluid only if it is in good condition.
Remove and clean the pan, fluid filter, and clip.
Loosen the rear servo adjusting locknut.
Pull the adjusting screw end of the actuating lever away from the servo body and insert the spacer tool between the servo accumulator piston and the adjusting screw. [cf2]Be sure the flat surfaces of the tool are placed squarely between the adjusting screw and the accumulator piston. The tool must not touch the servo piston and the handle must not touch the servo piston spring retainer.
Using a torque wrench with an allen-head socket, tighten the adjusting screw to 24 in. lbs torque.
Back off the adjusting screw exactly 11/2 turns. Hold the adjusting screw steady and tighten the locknut securely. Remove the spacer tool.
Install the fluid filter, clip, and pan with a new gasket.
Fill the transmission with the correct amount of fluid.