jeepete is correct on the output splines. the ba10-5 has 21 and the ax-15 has 23.
to convert from the ba to the ax, this is what i used, what needed to be done and how i did it.
>bellhousing...i called j&w and ordered one with an external slave. i think it came from a 4.0 engine since it has a cps mount on it. make sure you have the ballstud and spring for the throwout lever.
>throwout lever. cant remember the part number, but i can go from a parts diagram and tell you. i think i said 93 cherokee when i ordered mine at the dealer.
>clutch hydraulics. i used mopar part number 52104113. you will have to redrill the stud hole in the firewall, but thats no biggie. the 'carefull' hole is opening up the hole in the lollypop on the rod. the pedal's pin on mine is 1/2", and the lollypop's was 3/8". i took a bit and twisted it with my fingers so i wouldnt crack the plastic.
>new tcase input gear, 23 spline
>ax-15, where ever you get one, look for one with a small pilot or specify on the order. this way you can still use the factory pilot bearing. cherokee ax-15's will have the larger pilot. another thing to look for or specify is a 'long bearing retainer'. the external version has a throwout bearing that slides on the retainer.
>clutch, i used a Luk RepSet 05-901. the clutch disk and pressure plate are the same, along with the correct throwout bearing. pilot bearing you can get from the dealer. there may be a a set out there that has all the right parts but im not sure what it is. i think you can get one for a 97 tj with a 4.0 that is complete-complete. im not sure, but if you poke around on the web, you'll find the correct info.
>not required but recommened. a new skidplate. there was a change between the 87 and 90+ yj skidplates. getting the newer version would eliminate some cutting and drilling for the new mount.
>tranny mount. thats a no brainer. no telling what the condition is on the new tranny, if there is one.
something to be aware of is that jeep used 2 different front cases for the ax-15. you may need to replace that too, i have 2 different t-case shifters just for that situation.
>tranny shifter. the ba and the ax are different, so you will need one of those.
if you need a tranny service manual for the ax-15, my copy somehow made it to the pirate4x4 site and billavista made it a pdf (thanx billavista). i think i made a copy of it for someone and it got passed around. those are my notes on the pilot & pilot bearing dimensions on the front page. yes, i have the pdf.
its a fairly straight forward deal once you have all the parts. i called j&w and said this is what im doing...this is what i have, and sell me what i need. fantastic bunch of people out there
http://i7.photobucket.com/albums/y298/bowcouple2k5/jeep%20project/clutch1.jpg
http://i7.photobucket.com/albums/y298/bowcouple2k5/jeep%20project/clutch2.jpg
http://i7.photobucket.com/albums/y298/bowcouple2k5/jeep%20project/clutch3.jpg
there are no external slave kits that i know of for the ba's. the best and most reliable bang for the wheeling buck is the ax-15 conversion. i've had no problems with mine except where i used a pilot bushing that dried out and started to squeel. i just went to the small pilot and factory bearing and all is well. t-case mounts right up without modification except for the input spline. since you gotta get in there anyways.....its probably a wise choice to replace the chain and shifter pads of the t-case and do a sye conversion.
i did this conversion almost 10 years ago, so im running off memory power. if i think of something i missed, i'll add to it. if you have any questions, post em.
if any of you guys are around the atlanta area, look for a guy named norm kibe. last i knew of norm, he had a 97 tj. great guy, good mechanic and a good friend to have. hit norm up for some info, he'll be happy to help ya out. he's got the jeeper's heart. excellant drivetrain guy. norm, thanx for all the help and all the fun wheeling we did. yeah, we were right when we thought we were bein watched that weekend at tellico.