Tj ax15 swap

[DravenBoris]

Hey curious about some details on this. I have an 88 five speed 2wd. I found a guy with an ax-15 with 231 out of a 2000s tj. Will this swap? If so what all do I need and what do I need to do to make it work? Thanks for the help 

[87MJTIM]

Are you sure it is an AX15?  Didn't Jeep switch to a NV3550 around that time?

 

The NV will bolt up.  However, the tcase may not be clocked properly for the MJ.  You may have to reclock it.

 

I don't know if the cross member from a TJ will fit your MJ.  You may have to search for a proper cross member and trans mount (for an AX15).

 

You most likely will need to change the pilot bushing to fit a larger size input shaft tip.  Later model AX15s have ~3/4" tips.  A BA10 (assuming that is what you have) is only ~1/2".  Search for a pilot bushing for a 74 CJ5 with a 304.

[Pete M]

01 would be the first year for the NV trans.  I have a 2000 TJ AX-15 in my 88.   yes, the trans clocks the t-case up a bit, but I appreciate the additional ground clearance so I kept it as-is.

 

you'll need the bellhousing and its guts for sure.  and you'll want an XJ AX-15 crossmember for the slight drop in the middle (a crossmemebr drop can be added to accomplish the same task but at the cost of an inch of ground clearance lost).  and you'll likely want to source an XJ shifter handle/tower.  I used the TJ parts in mine and the shifter gets waaaay close to the dash.  I still run it though.  

 

I used the 304 pilot bushing.

[DravenBoris]

If these photos load, this is what I’m getting. I need to do a floor board job any way so I figured I’d “massage” a little to deal with clocking. But if the xj cross member clears it enough I’ll just get that. There’s one at the yard near me. It comes with everything clutch to transfer case, but I’m getting a 242 from a buddy to put behind it. Do the mj drive shafts happen to have a different yoke( the end that mounts)? I know I’ll need to shorten mine but i didn’t know if I needed to get a different end as well. 

[87MJTIM]

You need to keep your Renix flywheel.  The HO flywheels will not work with the engine computers.

[Pete M]

I do believe your 2wd yoke will have the wrong spline count for the new t-case.  what is the 242 coming from?

[Strokermjcomanche]

 Wasn't there an issue if you ran a 242 behind a standard transmission? 

 

I have an NV 3550 in my 88 with the AX 15 crossmember and no issues. I also have the TJ shifter but I kind of like it sitting up that high . 

[Pete M]

far as I know, all we know is that Jeep never offered it.  But since they won't tell us why, it could be a mechanical reason, or it could be a "we don't think the customer needs this" type of reason. 

 

But other owners have swapped them in and they seem to work just fine.   Just as long as it's not an 87-90 which would be 21 spline input.  Although a 2.5L owner could use that.

[coheed]

27 minutes ago, Pete M said:

far as I know, all we know is that Jeep never offered it.  But since they won't tell us why, it could be a mechanical reason, or it could be a "we don't think the customer needs this" type of reason. 

 

But other owners have swapped them in and they seem to work just fine.   Just as long as it's not an 87-90 which would be 21 spline input.  Although a 2.5L owner could use that.

From reading about the NP228/229, Jeeps reasoning was the selec-trac transfer cases had more slack in them. Some people speculated that the less consistent load of a manual and the higher shock load of a clutch could cause an issue with that slack. 

 

Though as you've said people have put both the 242, and the 228/229, behind manuals.

[DravenBoris]

1 hour ago, Pete M said:

far as I know, all we know is that Jeep never offered it.  But since they won't tell us why, it could be a mechanical reason, or it could be a "we don't think the customer needs this" type of reason. 

 

But other owners have swapped them in and they seem to work just fine.   Just as long as it's not an 87-90 which would be 21 spline input.  Although a 2.5L owner could use that.

 

5 hours ago, Pete M said:

I do believe your 2wd yoke will have the wrong spline count for the new t-case.  what is the 242 coming from?

 I believe out of a briar wood. Or a newer Comanche I’m not sure. I’ll have to ask my buddy has it 

[OldSch88L]

You didn't specify if your Comanche is a 2.5 or 4.0, but I went with a TJ AX-5 (from a 2.5L TJ) for my 2.5 Comanche. Like the others said, it clocks the t-case higher and hit my floor so I drilled new holes clocking it down about 10 degrees. If I recall correctly, the TJ tranny came with its trans mount still attached and bolted perfectly on the Comanche crossmember. I used a '96 242 t-case, and in my case (no pun intended) I had to switch the input shaft for a 21 spline (if you have an ax-15 you'll be golden since it's got a 23 spline output, and 90% of all the 242s have a 23 spline input) and like others have said, the 2wd transmission yoke won't work. Also if you can, try finding a 1992 or older 242 if my memory serves me well... On my '96 242, the 4x4 position switch is on top, and is so close to the floor that I can't put the connector on; I had to modify the switch. Older 242s had the switch on the back of the case. That was pretty much it!

[DravenBoris]

20 hours ago, OldSch88L said:

You didn't specify if your Comanche is a 2.5 or 4.0, but I went with a TJ AX-5 (from a 2.5L TJ) for my 2.5 Comanche. Like the others said, it clocks the t-case higher and hit my floor so I drilled new holes clocking it down about 10 degrees. If I recall correctly, the TJ tranny came with its trans mount still attached and bolted perfectly on the Comanche crossmember. I used a '96 242 t-case, and in my case (no pun intended) I had to switch the input shaft for a 21 spline (if you have an ax-15 you'll be golden since it's got a 23 spline output, and 90% of all the 242s have a 23 spline input) and like others have said, the 2wd transmission yoke won't work. Also if you can, try finding a 1992 or older 242 if my memory serves me well... On my '96 242, the 4x4 position switch is on top, and is so close to the floor that I can't put the connector on; I had to modify the switch. Older 242s had the switch on the back of the case. That was pretty much it!

 88 4.0, I forgot there’s other engines lol I only rock 4.0s. But the 242 is from a briar wood it is 23 spline and the ax-15 is 23 spline. Will the yoke from the 242 connect to my drive shaft after I get it the right length? Also the tj ax-15 has some electronic components and as far as I’m aware the the ba10/5 doesn’t have anything electronic. How do I work around this? Especially with the speedo. 

[Pete M]

you'll still need a later yoke.   the speedo hookup is in the t-case and while your speedo cable will be too short, you can still plug in like normal once you get a 4wd version.  you may need a long or short speedo gear shaft as I'm not sure which were used when.  you'll also need to splice in to the new backup sensor.

 

be sure to add the truck specs to you signature.  

 

 

[Sir Sam]

Personally I prefer the 96+  transfer cases as they have a different tail cone with a seal, so you can remove the driveshaft and not have the T case lose oil.

 

Might not seem like a big deal, but I've had to use my jeep as FWD when I had a ujoint/driveshaft failure.

 

Overall not deal breaker, but might as well get the "better" parts when doing a swap. And with 1996+ 242s being a dime a dozen might as well grab one.

 

I massaged the floor to clear the transfer case with my TJ Nv3550, you can also redrill the back of the trans to clock it lower. Plenty of meat there, when you get the trans you will see what I mean.

 

I'm not sure the TJ clutch line will work in an XJ, or at least it may not fit nicely, keep your eye out for an XJ setup.

 

XJ NV3550s are exceedingly rare, the manual trans went to special order only at that point. You had to specify your options and order the jeep from the dealer, so unlike the ax15 years, none just rolled off the line without a customer lined up for them.

[Pete M]

I'm assuming the 242 found under KJs would work?  they are quite common.

 

[Sir Sam]

Just now, Pete M said:

I'm assuming the 242 found under KJs would work?  they are quite common.

 

 

They will phsyically bolt up, but the KJ 242 does not have a speedometer pickup on the tail housing......further, the KJ 242 output shaft does not have the gears cut to mesh with the speedo gear, so its not possible to swap in a common 231/242 tail cone from a XJ or ZJ to get the speedo gear, you would need the tailcone and the output shaft. 

 

At least thats the way it was for the 2005ish+ tcase. I have a new clean 7k mile 242 from a KJ that I was going to use in the MJ, when the MJ was going to be a diesel it didn't matter since I would use the speedo pickup on the rear diff since I have a KJ 8.25. But now that I am going 4.6 stroker I need that speedo.

 

The WJs had the tail cone that had a place for the speedo pickup, but the opening wasn't machined out. My next thing to check is if a WJ 242 that has the blank spot has the machined shaft for the speedo gear. lots of WJ242s around.

 

If the WJ 242 has it, there is a decent chance the early 02-04 KJs are also the same way, but with the WJ discontinued in 2005 the 2005+ KJ might be different. Just something else I need to check out the next time I'm at the junkyard.

 

I have 2 good KJ 242s around, 3 if you count my wrecked CRD, and no spare XJ 242s.

[OldSch88L]

On 5/15/2020 at 3:58 PM, DravenBoris said:

 88 4.0, I forgot there’s other engines lol I only rock 4.0s. But the 242 is from a briar wood it is 23 spline and the ax-15 is 23 spline. Will the yoke from the 242 connect to my drive shaft after I get it the right length? Also the tj ax-15 has some electronic components and as far as I’m aware the the ba10/5 doesn’t have anything electronic. How do I work around this? Especially with the speedo. 

You'll only need to connect the reverse light switch, the rest doesn't matter. Sir Sam just reminded me that I also had to buy a custom clutch line and adapter to mate the TJ external slave with the MJ stock clutch master. I bought it from Advance Adapters IIRC. The yoke from the 2wd shaft won't work; different, type, diameter and spline count. You'll have to get the right yoke depending on what year 242 you have since some had an internal type slip yoke, and others had an external type. For speedo gears, the long shaft ones are for cable drive speedos, and short shaft for electronic.

[Pete M]

I mated my TJ slave line to my MJ master line with an adapter compression fitting from Lowes.  these are NOT to be used on brake lines, but the clutch sees a lot less pressure (and is a lot less deadly if it were to fail).  still holding strong  

[DravenBoris]

Hey curious. Since the transfer case is clocked different what shifting linkage and arm slash bezel do I use? Wanting to use Cherokee stuff but I did dmt know what would mesh 

[Pete M]

pretty sure all those parts are Cherokee on mine.   

[DravenBoris]

Thanks I’ve never done this kind of swap. It’s actually my first five speed and will be my first five speed swap. Just enjoy driving it too much to give up stick shift and no way in hell I'm I’m going t swap in another ba10/5

[DravenBoris]

On 5/26/2020 at 9:47 AM, Pete M said:

pretty sure all those parts are Cherokee on mine.   

 Does that new fancy shift arm linkage by azzy’s Work? 

[Pete M]

I've heard great things about it.    but I've not tried it myself.