OldManComanche

If you can find a pilot bearing that will fit the newer 4.0 engine crank and fit the early AX15 input shaft , that would be (by far) the easiest and cheapest way to go. I know someone is supplying a bearing like what you need. You need to measure ( with micrometer ) you input shaft, I think it is more like 5/8th inch. Good Luck!

I ran into this with a YJ/AX15 setup I had with a 97/4.0 engine. The transmission was worn out, so I rebuilt it and installed the later model (year correct for my engine) input shaft with a 3/4" pilot bearing. What shape is your transmission in? If it needs a rebuild you can change the shaft and retain the year correct pilot bearing and have a stronger input shaft setup. Note; the AX15 disassembly and reassembly is tricky but worth the effort. I also started using SAE 10w30 motor oil instead of 75w90 gear lube in the transmission. That greatly improved the shifting and drivability!

What are you trying to accomplish? Do you have mechanical issues like oil leak, exhaust smoke, reliability (won't start, runs poorly, engine noise, ect.)? Spending a bunch of money on parts that don't need changing is crazy. If it ain't broke, replacing it won't fix anything!

I don't think the wiring was great to begin with. I have had 3 Comanches, and all 3 have had wiring repairs that were POOR! Wire ends that had the insulation cut off and the dirty bare wires twisted together, or wire splices with much smaller gauge wiring being used. No tape or insulation of any kind. CLEAN WIRE ENDS, SOLDIER, AND SRINK TUBING ARE YOUR FRIEND!! (along with patience)

I had a problem like this. The wiring had been badly hacked up. I spent several days straightening out the wiring trying to find the problem, but no success. I was sitting in the truck wondering what to do when I noticed the cigarette lighter was pushed in. I pulled it out and noticed the end of it was warm to the touch and all crudded up. I left it out for a couple of days and the current drain went away. I guess that it acted like a big resistor and slowly drained the battery. Good Luck

AX15 is a good transmission, it has it's quirks. BUT you still need to pay attention when you work on it. In this day everyone is in a hurry. If they would slow down and check what they have done, you wouldn't have had to take it back and they wouldn't have had to fix it right the second time. (at least they fixed it)!! Daddy used to say: If you half A** it, you will end up with half A** results! Enjoy Your Truck!

GLAD TO HEAR IT! Did you get an explanation of what they did wrong?

Oh by the way, (BEFORE YOU INSTALL THE TRANSMISSION) stick the shift lever in and turn the input shaft. Observe the output shaft as you shift the gears; 5 gears and reverse.

MY GUESS IS; reverse shift fork is not engaged in the reverse sliding gear, OR reverse gear or linkage is missing OR improperly installed. Because 5th gear works and reverse doesn't. 5th and reverse are on the same shift rail. Be VERY CAREFUL if you drive the truck, you could get stuck with 2 gears engaged at one time. I agree with 87MJTIM, it needs to go back to whoever rebuilt it. If my guess is correct; the transmission needs to be completely torn down, The reverse gear installation is in the early stages of reassembly so everything needs to come apart to get to it. There is a wedge shaped piece sits on the end of the reverse shift linkage that shifts the reverse gear in and out. That is missing / fell out on assembly. Google; Jeep AX15 Service Manual Transmission. Excellent step by step AX15 disassembly and assembly GOOD LUCK

Does the gearshift lever actually move into the reverse position or is it blocked out of reverse?

Would it be a door opener control for The Bat Cave

Are you talking about manufacture advertised fuel economy or is this the mileage you are getting on 2 trucks you have or know of??

Glad to hear it, but I would wait till after a few more drives to celebrate. If everything is good then enjoy it!

Drive the truck till the problem shows up. Crawl underneath and unplug the speed sensor at the transfer case and try driving it. Does the problem go away? Good Luck!

You say that the speedo started bouncing again and your problem came back, maybe there is a link. Is the speedo cable driven or electric sender? You might try to unhook it and see if your problem goes away. You might also try driving in a lower gear at 2500 + RPM to see if the problem shows back up. This might tell you if it is a speed sensing problem (I doubt it), I would guess the ECU thinks the engine is over revving. 200 MPH REALLY?? I have a 1990 YJ Jeep. The original 4.2 I6 with carb had been replaced with a 97 HO I6. When I bought it it would barely run. Someone had done a half way installation, (kinda like your deal) of the Painless System. I cut it out and started over, (with the phone help of the guys at Painless). Now my Jeep runs like a fire truck on fire! But there was plenty of PAIN to get there!

What about pulling fuses out 1 at a time to see if you could isolate a circuit causing the problem. The wiring on all of the 3 Comanches I have had came with hacked up wiring.

I too had similar problems with the clutch not releasing after all new parts (pressure plate, disc, throwout bearing, and plastic bushing on the pedal end of the pushrod). I found that removing the carpet would allow the clutch to fully disengage. I made the pushrod adjustable and problem was solved. I found that adjusting the pushrod about 5mm longer gave me a clutch engagement at about half pedal travel. (89 Pioneer, 4.0, AX15 4x4)

When the transmission oil is cold and thick, it will act as a brake and stop the gears from turning in the transmission. This makes it easier to shift into gear. After you drive a bit, the oil thins and the gears want to keep turning. I actually made my clutch rod adjustable when I added length to it. I don't know what the root cause of the problem is, but I would guess that the replacement clutch components you can buy today are slightly different from original.

I had a similar problem with my 1989 4.0 / AX15. I replaced the complete clutch, slave cylinder, master cylinder. There was no air in the clutch system. You could get it into 1st gear and reverse when you first started the engine cold. After driving for a few minutes it would become very difficult to get into gear (hard to push into 1st gear and grinding reverse gear). I replaced the plastic bushing on the master cylinder rod and clutch pedal. It was a little better but not right. Removing the floor mat so the clutch pedal would go all the way to the floorboard helped a bit. I decided that the master cylinder piston was not being pushed all the way into its bore, there by not completely pushing the slave cylinder into the pressure plate and releasing the clutch. I added 5 mm of length to the master cylinder rod and my problems went away. It is surprising that the factory didn't include a way to remove the slack in the clutch pedal system. Does anyone know of an adjustable clutch rod?