Search the Community

Hello all, I’m new to the Comanche cluband am building my first MJ. I have a 98 XJ that I wheeled and drove since 2003. I recently totaled it and picked up a 1986 MJ for $600. Replacing the floor pan now, I plan on doing a Rusty’s long arm as well as swap the 4.0 and AW4 from the XJ. The MJ had a 2.8 with a manual, not sure if I need to cut the cross member mounts off the unibody for clearance with the trans or fitment with the long arm crossmember. Has anybody ran into this before on one of these awesome Jeeps? I really have been getting a lot out of all the experience posted on this forum. Cheers!

Hello friends. Jess here from Placerville, CA. I've been lurking around here for several years and have been so grateful to have such a fantastic resource. You guys rock! I can only hope to one day return the favor and give useful advice to someone in need. I don't have the technical knowledge many of you have and this certainly won't be the end-all AX15 swap thread but I figured I share my experience and if it helped someone out, awesome! First of all, there is a lot of posts about the AX15 - If you can't find what you need here on CC there is a lot of other AX15 swap threads out there, I found this thread on naxja particularly useful. I also picked up a FSM from Pacific Coast Manuals. Best $7.95 I think I could have spent, especially when it came to finding torque specs. Another good resource for parts if you're in the Sacramento area is J&W Auto Wreckers - I find their prices are a tad on the high side (basically double of most Pick & Pull parts) but they appear to have pretty much everything, including the AX15 bracket which was difficult to find and you don't have to bring your tools and roll around in broken glass. So, I have a 1989 MJ which of course had a Peugeot BA10/5 with the NP231. The internal bearings went and my second gear synchros have been out since I got the truck 6-7 years ago. The repair shop (I tried several, price always the same) wanted $850 to repair the bearings/synchros. I've always wanted to swap for an AX15 but never really had a reason until now. I found one out of a 91 Cherokee with 150k miles in a wrecking yard for $500 with the bellhousing and another $200 for the factory mated NP231. I probably could have swapped the input shaft for a little less, but honestly it was taking so long already I figured it was worth it to get the new one and go. Dropping the Trans: Having the right tools for the job would have made this much easier. Unfortunately we had none of those. If you don't either, I'd recommend renting or borrowing a transmission jack. It was always my plan to do that but my Dad and I backyard mechanic'd it pretty good instead. Our jack died recently, so we borrowed a neighbors which is hilariously tiny for removing a transmission. We used it pretty much for the wheels only. What we did was place a strong steel pipe above the trans tunnel/shifter hole and wrapped a large ratchet strap around the pipe and transmission. This supported it and allowed us to guide the transmission back out of the pilot bearing. Another thing that helps which we didn't have is level ground. Our driveway has a slant to it so we decided to park the truck facing down, which meant pulling the transmission uphill to remove it. I attached a strap from the jack to the rear bumper and a second from the t-case to the bumper, ratcheting both at the same time to back the trans out. It would have worked beautifully except we forgot one of those small bolts at the top of the bellhousing :( Once we got that it it popped right out, go figure. :dunno: We basically used the same strategy to reinstall the AX15, we took the t-case off and used two straps from that same pipe to raise the AX15 up and guide it in. It's not a perfect alignment, there's definitely some precarious finagling but it worked. Yep, zipties. A third strap was added to the axle of the jack to pull it and the trans back simultaneously. Bracket/Mount: My biggest unknown was the mount vs bracket. As I mentioned above I found the "bracket" to be rather elusive. I read several posts where people said they used the Peugeot crossmember with the AX15 mount and it was fine - but since the AX15 mount lacks the catalytic converter support arm I wasn't really sure how that was possible without fabrication work which I don't have the tools to do. If you cannot find the bracket or fab your own, you might try this AX15 Crossmember Mount Kit from Advance Adapters. They told me it would work fine in Comanches but considering the cost difference between having to replace the Peugeot mount vs AX15 mount I decided to try harder to find the bracket. Which I did find for $30 at J&W Auto Wreckers. Top left: AX15 "mount". Bottom left: AX15 support bracket. Right: Peugeot mount. Crossmember: To save myself $70 for an AX15 crossmember I used my original Peugeot one. Since the AX15 has that little dip in it I decided to get some longer bolts and use heavy nuts as spacers to allow the AX15 to sit properly. The crossmember had to be moved to the rear set of holes on the body, which meant taking a sawzall to one of the studs as I couldn't get it out with the other tools I had. Some of the original holes threaded fine, but three of them needed to be chased (10x1.5). Here you can see the nut spacers and new bolts. Transfer Case Linkage: I read several posts where people said you can flip the bracket which bolts to the transmission and make the Peugeot linkage work with the AX15. We popped it out and flipped it, the problem was by flipping it I took it to mean - removing it and plugging it into the same hole from the reverse side. We couldn't make that work at all. So we tried flipping it the other way, plugging it into the smaller hole on the other side of the bracket and bolting the grommet side to the transmission. After some finessing I was able to get it to work - it probably won't last forever but you know, it was free. Reverse Switch: I just cut the connectors off both the AX15 end and the Peugeot end and used quick disconnect connectors. I was out of shrink tube so I wrapped it all up in electrical tape. While I was at it: I had an oil leak so I changed the oil pan gasket, which thanks to advice on a thread I posted it was easy to remove the oil pan without the transmission in. I went ahead and replace the rear main oil seal and the oil pump as well. Conclusion: So glad it's done and I love this thing. I love the way the shifter feels and I think it's a lot quieter. Also huge bonus, I can use second gear lol. I'm so used to having to baby second gear that I still flinch when I shift, anticipating gears grinding. It's not all perfect though - there is an oil leak someplace. It seems to be coming from inside the bellhousing which is making me think the seal on the transmission is bad. I used Mobil-1 10w30 in the AX15 per some recommendations so I can't tell the difference between it and engine oil. It could also be the rear main seal which would also totally suck because that was a huge pain to change. Reverse gear is being a pain to shift into as well, we may need to bleed the clutch again, or something could be going on - I dunno. Right now I'm just happy it's running :yes: Jess