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89 4x4 Conversion And AX15 Swap HELP


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Hello, I have a lot of issues...

I bought a 89 2WD 4.0L Comanche a while back. I pulled the trigger on converting it to 4x4 and while doing that I was able to find a AX15 with the transfer case from a 94 Cherokee.

I pulled the front and rear axle out of a 87 4x4 Comanche that was thrashed, pulled the 2WD trans and TCase out.

Here's where it gets kinda funky... Skip to HERE'S WHERE I'M STUCK IF YOU DON'T WANT TO READ ABOUT INPUT SHAFT LENGTH THAT I SOLVED

I tried for about 3 days to get the transmission to slide on (after replacing all the clutch components of course). I had issues with the pilot bearing but did find one that was a nice fit after some research. Having tested that the inside diameter was right by simply sliding on the input shaft before installing it in the crank I knew that wasn't going to be an issue.

I slid the input shaft through the clutch and it stopped about 3/4 of an inch from mating to the motor. 3 days later and a lot of head scratching i decided to cut the tip off the the input a little to see what it would do and it went on further.... So I did some measuring and cut it off appropriately, it did bolt up just fine after that. 

----------> HERE'S WHERE I'M STUCK...  <----------

The crossmember is roughly 4 to 6 inches back to far to mount all 4 bolts, I could only get 2 in. The rear driveline is 4 to 6 inches to long. The front driveline is 4 to 6 inches to short. Where the shifter goes through the trans tunnel is 4 to 6 inches back towards the rear to far I can't even get the shifter on the transmission.

I have been stuck here for months, everything I read states it should all bolt up, the transmissions are the same length ect ect.

Was I supposed to use the old bellhousing or something? Any incite would be AMAZING!

 

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What transmission did you have originally - BA 10/5 or AX15?  (89 was a transition year from the BA to AX.)

 

You need the cross member for an AX to work.  

 

The MJ has the holes to fit either the BA or AX cross member.  I can see the extra holes in your photograph.

 

The drive shaft will have to be shortened to allow for a tcase.  The DS from the XJ will not fit.

 

Something doesn't seem correct with your description and photos.  The BA and AX are roughly the same length.  Yours should not sit that far back.

 

Did a PO make other "mods" to the truck?

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8 hours ago, Killernoise said:

 

I slid the input shaft through the clutch and it stopped about 3/4 of an inch from mating to the motor. 3 days later and a lot of head scratching i decided to cut the tip off the the input a little to see what it would do and it went on further.... So I did some measuring and cut it off appropriately, it did bolt up just fine after that. 

Something went terribly wrong here. 

You cannot cut the input shaft. 

Your transmission is destined to fail .

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I believe i had a ba10 in it before. I got the drivelines from a 4x4 comanche. I can get a xj crossmember pretty easy around here. As far as the input shaft goes i measured the depth of the hole in the back of the crank with the pilot in the hole. It tapered. At the deepest part of the hole there was still not enough room. The tip of the shaft was cut just enough, it didnt affect any splines. Based on measurements it is still in the pilot bearing and seated correctly. I cut maybe 3/16 off of the tip of the shaft. 

20190803_192559.jpg

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1) input shaft aside

2) rear driveshaft would not fit anyway

3)can you post a picture of the round silver tag on the rear of your transfer case? 

4)Can you post a pic of a side shot of your trans.

 

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There's no tag on the TC anymore, but I did pull it off and on a few times before installing and it fits fine, I also got this AX15 and tcase together from a buddy that pulled them from a 94 so they were mated at factory. The last pic shows that the motor and trans are flushly mounted and tight.

1.jpg

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4.jpg

Inked2_LI.jpg

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You need the transmission tunnel cover plate (the thing that's under your ripped up carpet in your first pic) for an AX-15.  Each transmission (AX4/5, Puekgoat, AW4, AX15) has a unique cover plate with a cutout to match the shifter throw of each transmission.

 

Learned this the hard way when I converted mine and tried re-using the AX5 cover plate I had.

 

Also, you really need an AX-15 crossmember for everything to line up correctly in the vertical position.  I can't really tell by your pics, but it looks like the one you're using is not for an AX-15.  The correct one has a depression in the center section where the mount bolts up (all of the other crossmembers are level straight across).  The others will "work" per se, but the trans will sit too high in the tunnel.  The exhaust flange at the cat converter will be kissing your floorboard, and the factory shifter linkage will not line up correctly.  Also on that linkage....you'll need both the AX-15 shift rod (it is a medium length, the other tranny ones are either too short or too long), and you'll need the specific AX-15 bracket that bolts to the underside of the tranny tunnel that has the little swivel/ball/heim thingy in it.  That swivel is at the rear of the AX-15 bracket, all of the other ones it's centered and will not line up.

 

 

 

 

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I'm not sure what most of the things people are saying have anything to do with the fact that the transmission itself is way to far back. If I pull off the tcase and pull off the crossmember and just hold it up with a jack, the trans itself while being bolted to the engine will still be back to far for me to do anything with it.

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On 12/26/2019 at 6:09 PM, yxmj said:

you have a pic of the trans with light coming in by the shifter hole ...on the bottom of the trans I can see stamped numbers....can you post a pic of the numbers?

 

On 12/26/2019 at 2:37 PM, yxmj said:

What is the measurement of the front axle u joint pocket to the front t-case u joint pocket?

 

On 12/26/2019 at 7:15 AM, 87MJTIM said:

Did a PO make other "mods" to the truck?

On 12/27/2019 at 6:45 AM, mjeff87 said:

You need the transmission tunnel cover plate (the thing that's under your ripped up carpet in your first pic) for an AX-15

 

On 12/25/2019 at 11:05 PM, Killernoise said:

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All the above quoted questions are legitimate and still awaiting an answer. The people on here know their stuff and are willing to help, but since they aren't there looking at the truck in question some information needs to be verified first. Bear with it, hang in there, and something will get figured out. Yes it may seem redundant or irrelevant, but go with it. This is really a good forum and people genuinely want to help. So plan on getting them lots of information and photos. 

 

On the photo of your 'too long' driveshaft: Is that a 2wd drivshaft? If so then it will be too long for sure. I know you posted that you got the drivelines from a 4x4 comanche, but it doesn't match what I have in my truck. Can anyone else chime in on this? 

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A PROPERLY MOUNTED AX15 bolted to a PROPERLY MOUNTED 4.0 should not be sitting as far back as yours is sitting.  I have to guess that there is something else wrong that is pushing everything back.

 

(Just throwing stuff to see what sticks.)

Were the motor mounts changed that pushed the engine back? (Although there is not a lot of room to do that.)

 

Is the bell housing correct for the trans? (A BH that is too long would not explain have to cut the input shaft tip.)

 

Is the trans an AX5 (not a 15)? I don't know what the length difference is .

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On 12/25/2019 at 9:05 PM, Killernoise said:

The crossmember is roughly 4 to 6 inches back to far to mount all 4 bolts, I could only get 2 in. The rear driveline is 4 to 6 inches to long. The front driveline is 4 to 6 inches to short. Where the shifter goes through the trans tunnel is 4 to 6 inches back towards the rear to far I can't even get the shifter on the transmission.

I have been stuck here for months, everything I read states it should all bolt up, the transmissions are the same length ect ect.

Was I supposed to use the old bellhousing or something? Any incite would be AMAZING!

 

Your crossmember is NOT 4-6" too far back.  Currently it is about 1" too far back.  With the AX-15, AW4, and NV3550 it goes in the back two sets of threaded holes in the uniframe.  You can see the forward holes for the rear set of holes in this picture.

 

mjxmember.jpg.1dc7460fff64758281d38148c8c41b7c.jpg

 

My personal guess is that you have a few things not quite right and it's caused enough of a stackup of tolerances to get you here.  My first bet is you have the transmission mount (the rubber part) on backwards.  Yes, it goes one way, it's got a slope to it and it goes with the high part forwards.  From there I bet you have the mount plate not pushed as far forwards as it should be where it bolts to the bottom of the tranny, there is some slop in these holes.  Also, I believe you have the wrong crossmember, it looks like the original BA one, you can get away with using it but it isn't quite right as it pushes the transmission higher, you may have contact issues.  You may need to loosen all mount related hardware, and even the motor mount bolts slightly, in order to push everything forwards a bit.

 

The hole for the shifter was addressed before.  It is in a different place and shape in that floor cover plate depending on transmission.  I would look for the right one or hog the hole out.  Well, honestly I'd hog the hole out, but I've got some fabrication experience.

 

As to you front driveshaft, I have no idea what you got it from.  There is a bunch of different lengths based on configuration, I forget which are longest.  They also have a slip yoke so they will telescope.  Using the wrong crossmember won't help this as the output is higher.

 

What pilot bearing did you find that would fit?  AFAIK there is no pilot bearing that is the correct dimensions to do what you're doing.  There is a bushing, but bushing =/= bearing.

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25 minutes ago, DirtyComanche said:

 

Your crossmember is NOT 4-6" too far back.  Currently it is about 1" too far back.  With the AX-15, AW4, and NV3550 it goes in the back two sets of threaded holes in the uniframe.  You can see the forward holes for the rear set of holes in this picture.

 

mjxmember.jpg.1dc7460fff64758281d38148c8c41b7c.jpg

 

 

 

Just to mention, when I converted my MJ from 2.5 (AX5) to 4.0 (AX15) that stud pictured was in my way, and I removed it.  Like DC and others say, the AX15 uses the rear sets of holes in the frame and frame bracket to mount the crossmember.  It looks like the rear frame bracket hole on yours has a broken off bolt inside of it.  Either drill it out and retap it or remove the weldnut from the bracket via your favorite method of choice and use a new nut/bolt there.  I'm betting you'll need to pound out that stud on both sides to get the crossmember properly located.

 

Also, on the rear shaft.....those "tube-in-tube" style shafts were used on 2WD drive MJ's (I can't say exclusively, but I've never seen one on a 4wd MJ).  They really can't be cut down to fit because there's a rubber isolator/sleeve inside the 2 different tubes at the yoke ends.  If I had to wager, I'd say it was a 2WD shaft, and it's too long.  For the front shafts, there's at least 3 different sizes of them as well, depending on what transmission was in the vehicle it came from.  Each trans uses a different length shaft.  I want to recall from memory that the AW4 was the longest, AX4/5 were the shortest, and the AX15/BA10/5 are intermediate length between the two.

 

I (and others) think you're about 95% there, you just need to button up a couple little (important) things.  :beerchug:

 

edit: and one other little important thing....if you are using the correct AX15 crossmember (still in question), it is NOT symmetrical.  In other words, if things don't line up 100% on both sides, take it off and spin it 180 degrees and reinstall it.  Little differences in hole placement make a big difference on this.  I was stumped for a good couple hours on this problem until I figured out the problem.  From then on, every time I took the crossmember off I made a witness mark on it to make sure I put it back on in the correct orientation.

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Hate to really jump in on this but y’all caught me at the trans crossmember. According to the catalog, the 2.5L’s trans, AW4 and the BA use the same crossmember. As stated above the AX15 does indeed use a newer “type 2” crossmember as it is dubbed in the catalog. 

 

Just wanted to make that known. Have fun!

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2 minutes ago, mjeff87 said:

 

Just to mention, when I converted my MJ from 2.5 (AX5) to 4.0 (AX15) that stud pictured was in my way, and I removed it.  Like DC and others say, the AX15 uses the rear sets of holes in the frame and frame bracket to mount the crossmember.  It looks like the rear frame bracket hole on yours has a broken off bolt inside of it.  Either drill it out and retap it or remove the weldnut from the bracket via your favorite method of choice and use a new nut/bolt there.  I'm betting you'll need to pound out that stud on both sides to get the crossmember properly located.

 

Also, on the rear shaft.....those "tube-in-tube" style shafts were used on 2WD drive MJ's (I can't say exclusively, but I've never seen one on a 4wd MJ).  They really can't be cut down to fit because there's a rubber isolator/sleeve inside the 2 different tubes at the yoke ends.  If I had to wager, I'd say it was a 2WD shaft, and it's too long.  For the front shafts, there's at least 3 different sizes of them as well, depending on what transmission was in the vehicle it came from.  Each trans uses a different length shaft.  I want to recall from memory that the AW4 was the longest, AX4/5 were the shortest, and the AX15/BA10/5 are intermediate length between the two.

 

Good point on the studs for the crossmember.  I looked right at it and didn't register that it is a stud and that they were studs from the factory.  Tip for OP to remove it, spin two nuts part way down on it and tighten the nuts gorilla tight to each other, but do not tighten them against the uniframe.  If you have them tight enough against each other you should be able to put a wrench on one of the locked together nuts and turn the stud out.  Worst case the studs will strip or break rather than coming out, and you can carefully trim the stud off with a die grinder, angle grinder, dremel, hacksaw, etc.  There's a decent chance that with the studs out of the way the crossmember will more or less just go where it wants to.

 

That other hole may have a broken bolt in it, or it might just be dirt...  Worst case you do not need to put a bolt in it, as the XJ did not have them.  Personally I'd fix it, but I know lots of trucks don't have them.

 

Also good point on the 2wd shafts with the rubber isolator in them.  They are throwaway and not recommended to be cut down.

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I used a BFH to remove the studs on mine (there may or may not have been a serious amount of beer involved that day):laugh:

 

And here's a shot of the AX15/crossmember in my MJ.  I used to have a better pic of just an AX15 and an AW4/AX5 crossmembers sitting side by side on the floor, but all of those went away with Photo#%!-it.  At least you can see the center section which is divoted to put the driveline at the right height so everything plays nice together.

IMG_2355.JPG

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4 minutes ago, eaglescout526 said:

Hate to really jump in on this but y’all caught me at the trans crossmember. According to the catalog, the 2.5L’s trans, AW4 and the BA use the same crossmember. As stated above the AX15 does indeed use a newer “type 2” crossmember as it is dubbed in the catalog. 

 

Just wanted to make that known. Have fun!

 

It's almost identical to the other crossmembers but they dropped the middle of it by about an inch.

axcrossmember.jpg.8d197a970b9a636a725a04f0920a3620.jpg

 

othercrossmember.jpg.637b22556c7bd13bc585e094648e3718.jpg

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OP, where are you located?  (that profile thingy really does help if filled out).  If you're reasonably close to me I would be willing to come and eyeball what you've got going on.  That's about the surest way for me (or anyone else) to help you figure out what you've got going on there.

 

If you're not local-ish to me, maybe there's another member close enough to you that can put some feet on your ground and see what's up.

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Sorry everyone, I was getting an email with each reply from you guys and then it stopped I figured the thread died out. Obviously I'm quite frustrated with whats happening, and I am not thinking clearly here. I live in Oregon, its been very rainy and just bad weather in general so i have not gotten a chance to go outside and take a peak. I will start with looking at the motor mounts so see if they have ever been modified (doubt it though) or if the bushings are completely shot and letting everything move. As far as the crossmember, yes its still the BA10s factory. I wasn't givin the correct XMember with the AX15 when I got it. The F/R drivelines are actually from a 86 2.4 V6 4x4 long bed Comanche. I wasn't sure if they would fit and I did have my doubts. So i'm not to set back by that. I am sure I can find some correct length ones after I get everything else set up right. 

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