98 4.0L to ax5 pilot bearing

[0regon]

Hi.  I'm swapping a 4.0 from a 98 xj into my 88 mj which has an ax5 trans. I've hit a wall finding the correct pilot bearing. To my knowledge the ax5 was not an option in a 98xj and the ax15 has a different size input shaft.  The bearing from the 88 mj has a slightly larger outer diameter at the output shaft of the 4.0 so searching for that doesn't work either.. Anyone run into this or know specific bearing dimensions to search for?   Thanks

 

88mj 4.0 ax5 np231 d44

98xj 4.0 aw4 np231 8.25

[87MJTIM]

Are you sure you have an AX5?  The AX5 (and AX4) were only behind the 2.5 4 cyl.  The AX15 came behind the 4.0 6 cyl.

 

The trans input shaft tips were larger for later model AX15s than earlier model.  The early years (89-94?) have 1/2" tips; later years (94?-01) have 3/4" tips.

 

You will need a pilot bushing for a 74 CJ5 with a 304 engine.  The otter diameter and inter diameter will fit the later year AX15.

[0regon]

11 hours ago, 87MJTIM said:

Are you sure you have an AX5?  The AX5 (and AX4) were only behind the 2.5 4 cyl.  The AX15 came behind the 4.0 6 cyl.

 

The trans input shaft tips were larger for later model AX15s than earlier model.  The early years (89-94?) have 1/2" tips; later years (94?-01) have 3/4" tips.

 

You will need a pilot bushing for a 74 CJ5 with a 304 engine.  The otter diameter and inter diameter will fit the later year AX15.

Thanks!

 

I kept doing research after posting and I think I must have the AX15! The previous owner’s records said AX5 and I should’ve known better.  It wouldn’t make sense to have a AX5 with a 4.0 and a Dana 44.. 

 

So I guess what I’m looking for is the 1/2 inch (older style AX15 tip) with the newer 4.0 outer diameter. 

 

I ordered another bearing today (that I now think might still be wrong) the parts guy said was for an 82 cj with an inner diameter of 5/8”.   

 

Ill look into the 74 CJ5 but if that’s a match for the newer AX15 it’ll be a 3/4 inner dia. Instead of the 1/2” that I’ll need..

 

 

[Pete M]

can we get a quick pic of what you've got?  just want to be sure we''re all on the same page.   

[0regon]

I guess I should give a little more background on what I’m doing.. I’ve got a stock 88 mj  4.0 AX15 (pretty sure now) np231 d44. Had low compression in cyl 4.  I had a spare motor for my 98 xj (AW4 np231 8.25)  I decided it was easier to just swap in my spare than rebuild the original. I’m keeping the original tranny transfer case Renix stuff etc.  I’m following cruiser54’s “HO swap into Renix” pretty much exactly.

 

I pulled the bearing on the left from the original 4.0 in the mj. The inner diameter is correct But (after some pounding) I realized the outer diameter is bigger than the output shaft on the 98 4.0 I’m swapping in.  So I hastily bought the bearing on the right which is for a 98xj. The outer diameter is correct for the 98 4.0 I’m swapping in but obviously the inner diameter is way too big.  

 

In in short I need a bearing with the inner diameter (1/2”) on the left and an outer diameter (?) of the bearing on the right.  I’m just having a hard time knowing what to search for..

[87MJTIM]

I didn’t think to ask previously, does your transmission have an internal slave or external slave cylinder?

 

an external slave may indicate a later years model. 

[OldManComanche]

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!

[0regon]

I believe it’s an internal slave. I have to admit I’m pretty new to the manual transmission game. Just never had problems with clutch or trans in the past..  

 

As for the condition I think it’s pretty good but I’ve only put about 1000 miles on this mj.  Other than replacing a leaky master I haven’t had any problems. The tranny and transfer case look real fresh and clean like they were rebuilt recently.  The history of this mj is a little mysterious.  It’s only had 6k miles put on it since 2007 with great records kept till 2014 then nothing but almost no miles on the clock till I bought (rescued) it.  Somewhere in between the trans and t case were refreshed and barely driven..

[87MJTIM]

Probably the earlier AX15.  Tip is probably (looks like) 1/2".

 

Don't need the 74 CJ5 bushing.

[0regon]

6 minutes ago, 87MJTIM said:

Probably the earlier AX15.  Tip is probably (looks like) 1/2".

 

Don't need the 74 CJ5 bushing.

Yup I'm pretty sure that's exactly what I've got; earlier AX15 with a 1/2'' tip.  No work today so I'm off to Napa with both my half wrong bearings and a set of calipers.  Crossing my fingers I can find something that works.

[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!

[0regon]

2 hours ago, OldManComanche said:

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!

That's exactly what I'm hoping for.  I haven't measured the input shaft but the bearing I.D. is 1/2" and the O.D. needs to be 1". with such round numbers you'd think it would be easy to find. Apparently it's not.  After spending some time at Napa going through "the old national bearing book"  with no success I went to a local industrial supplier who also couldn't find a bearing with those dimensions... So, I ordered a bushing with a I.D. of 1/2" and a O.D. of 3/4".. I have a bearing to fit the new AX15 input shaft (3/4")  I'm not sure if it's going to work but I'm running out of time so the plan is to give the bushing and 3/4" bearing a try.. If that doesn't work I'll have to rebuild the trans with a new input shaft..  Here's hoping it works out to be less sketchy than it sounds. I'll know on Monday when the bushing arrives

[87MJTIM]

Rockauto lists several pilot bearings:  https://www.rockauto.com/en/catalog/jeep,1988,comanche,4.0l+242cid+l6,1181584,transmission-manual,clutch+pilot+bearing,1964

 

[OldManComanche]

Rebuilding the transmission with the late style 3/4" input shaft/pilot bearing IS EXACTLY WHAT I DID when I was in this exact situation.(97 motor / 89 AX15). You can use the correct pilot bearing for the later motor with the AX15 3/4" input shaft. AND you have a better transmission input setup, there is a reason they went to larger shaft and bearing. Remember you will have to tear the trans completely down to put the input shaft in, I isn't just unbolt the snout off of the transmission and change shafts!! If you decide to go this way let me know and I can point you  to good trans rebuild instructions!

[0regon]

34 minutes ago, 87MJTIM said:

Rockauto lists several pilot bearings:  https://www.rockauto.com/en/catalog/jeep,1988,comanche,4.0l+242cid+l6,1181584,transmission-manual,clutch+pilot+bearing,1964

 

Thanks for the link.. unfortunately I don't think any of those will work. 1.055" outer diameter will fit the old engine but the newer style has to be 1.000"  It's a small difference but it's the reason the bearing on the left is my above picture is all mangled.  

 

43 minutes ago, OldManComanche said:

Rebuilding the transmission with the late style 3/4" input shaft/pilot bearing IS EXACTLY WHAT I DID when I was in this exact situation.(97 motor / 89 AX15). You can use the correct pilot bearing for the later motor with the AX15 3/4" input shaft. AND you have a better transmission input setup, there is a reason they went to larger shaft and bearing. Remember you will have to tear the trans completely down to put the input shaft in, I isn't just unbolt the snout off of the transmission and change shafts!! If you decide to go this way let me know and I can point you  to good trans rebuild instructions!

I think this is the real solution and if you can point me to those instructions I'd appreciate it!   I do my best to do good work and I appreciate a real solution even if it is a lot more involved.. That said I might still have to band-aid the problem for now. When I said I'm running out of time I mean that I sold my house and we close on the 11th!  One way or another I gotta get my MJ out of the garage soon! 

[Pete M]

a custom milled bronze bushing is always an option.  

[OldManComanche]

I thought the "small pilot bearing shaft" was closer to 5/8th inch (.590") 

 

The Jeep I was working on (YJ) had a custom made bushing that had the pilot shaft hole egg shaped. I don't know if it was poor workmanship, soft brass, or just plane poor setup. It was worn so bad that you could put your thumb through the hole.  It ruined the end of the input shaft, clutch, gears, bearing, syncro, and sliding hub.  I went the way I did because I was already going to have to change the input shaft, so why not go to the later style, larger bearing input shaft. 

 

I AM SURE THERE IS A SORCE FOR A PILOT BEARING THAT WILL FIT LATE CRANKSHAFT TO EARLY PILOT SHAFT.  If you are in a jam, do like Pete M says and have someone locally make you a bushing.

 

I found the complete disassemble and reassemble procedure at SCRIBD.com,..  look for Jeep AX 15 service Manual Transmission. They let me look for free and then blurred the images and wanted money later.  Instructions and images were excellent.

 

  Daddy used to say: If you half a** something, you get half a** results! And if you half a** it again all you have is one whole a**!! It took me a long time to learn this.

[amsuco]

It's a shame the OP has a time crunch situation.  If I had it tore apart like he has, I'd take the opportunity to swap to an external slave if at all possible.

[Green Mesa XJ]

Is the OP sure it is a AX15? AX5 looks similar, if the previous owner was halfassing the build lord knows what he grabbed

I thought somebody would have run into this problem before and there would be a solution. the few who had this issue either built a custom bearing or swapped the crank




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[Green Mesa XJ]

Never mind looking at the ax15 in the garage it appears the one in the photo is ax15,
wouldn’t be a bad idea to swap it to external slave cylinder. The throw out bearing retainers can be cheap on eBay, that’s where I got mine .


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[OldManComanche]

Do you have a machine shop, friend etc. that can machine the OD of the bearing you have down to the dimension you need for the later engine?

[BeatCJ]

It's not difficult to do. If you don't mind an Oilite bushing, you can be successful with just the correct size drill bit. Get a bushing that fits the crank, then just ream the inner bore to fit. I have also made it work chucking one with the right inner bore work with a file, an expansion arbor and a drill press. Not the right way, but when needs must...

 

Added Edit: You could also Contact Novak, they make adapter Pilot Bearings and Bushings. It might make sense to call them and see if they could Next Day ship for you.

 

https://www.novak-adapt.com/catalog/pilot-bushings/amc-ax15/

 

And, worst case, load your Comanche on a car trailer, and move it that way. Where in Central Oregon? It's not a horrible drive to Bend for me.... Heck,that might even be the best case, instead of rushing. Load your parts into plastic totes, then you have more time for other things.

[OldManComanche]

If you could use the expansion arbor on the needle bearing and do as you suggest, just reduce the OD it would be just about like factory. I am not familiar enough with the expansion arbor to know how that might work. The needle bearing might allow the outer diameter to free wheel and no material would be removed.(I'm not sure)  If it would work, the bearing the OP tried to use could then be made to work.  I like it! Take what you have and make it work!

[0regon]

Wow, lots of good input since I checked this last! Thanks guys!  

I'll see if I can cover all this in one post

20 hours ago, OldManComanche said:

I thought the "small pilot bearing shaft" was closer to 5/8th inch (.590") 

 

The Jeep I was working on (YJ) had a custom made bushing that had the pilot shaft hole egg shaped. I don't know if it was poor workmanship, soft brass, or just plane poor setup. It was worn so bad that you could put your thumb through the hole.  It ruined the end of the input shaft, clutch, gears, bearing, syncro, and sliding hub.  I went the way I did because I was already going to have to change the input shaft, so why not go to the later style, larger bearing input shaft. 

 

I AM SURE THERE IS A SORCE FOR A PILOT BEARING THAT WILL FIT LATE CRANKSHAFT TO EARLY PILOT SHAFT.  If you are in a jam, do like Pete M says and have someone locally make you a bushing.

 

I found the complete disassemble and reassemble procedure at SCRIBD.com,..  look for Jeep AX 15 service Manual Transmission. They let me look for free and then blurred the images and wanted money later.  Instructions and images were excellent.

 

  Daddy used to say: If you half a** something, you get half a** results! And if you half a** it again all you have is one whole a**!! It took me a long time to learn this.

I've got a brass bushing ordered that should be here by Monday. I don't like the idea of using a bushing much though and while I wait I'm researching other options and continuing to look for a pilot bearing that will fit.   Thanks for the AX15 info I will look onto that!  If I have to band-aid it now and pull the trans out in the future that's what I'll do!

 

15 hours ago, amsuco said:

It's a shame the OP has a time crunch situation.  If I had it tore apart like he has, I'd take the opportunity to swap to an external slave if at all possible.

Couldn't agree more!  When I started this project I had a lot more time! I figured I could easily do the engine swap in a weekend or two. I've had my replacement engine ready to go in for almost three weeks now with just a pilot bearing holding me up!  I have to admit I don't know a lot about transmission stuff so I'm taking this opportunity to learn as much as I can. I will look into an external slave swap for sure! 

 

6 hours ago, OldManComanche said:

Do you have a machine shop, friend etc. that can machine the OD of the bearing you have down to the dimension you need for the later engine?

Hadn't thought of that!  The bushing I ordered is right next to the machine shop I use. I'll ask them on Monday if that's something they can do!

 

2 hours ago, BeatCJ said:

It's not difficult to do. If you don't mind an Oilite bushing, you can be successful with just the correct size drill bit. Get a bushing that fits the crank, then just ream the inner bore to fit. I have also made it work chucking one with the right inner bore work with a file, an expansion arbor and a drill press. Not the right way, but when needs must...

 

Added Edit: You could also Contact Novak, they make adapter Pilot Bearings and Bushings. It might make sense to call them and see if they could Next Day ship for you.

 

https://www.novak-adapt.com/catalog/pilot-bushings/amc-ax15/

 

And, worst case, load your Comanche on a car trailer, and move it that way. Where in Central Oregon? It's not a horrible drive to Bend for me.... Heck,that might even be the best case, instead of rushing. Load your parts into plastic totes, then you have more time for other things.

Not sure I understand this idea.. Do you mean drill out the crank to the O.D. of the older bearing?   I also don't know what an expansion arbor is! I'll google it! 

 

thanks for the Novak link I'll get on that asap!

 

I do have access to a car hauler and I'm looking into some backup plans in case I can't get this thing together before I move. I'm in Redmond now and moving to Bend.  I'll be living in a studio with no garage for awhile but I do have friends in the area who might be willing to let me wrench in their shops if need be.. 

 

[BeatCJ]

Not on a needle bearing, but a brass bushing. It used to be that we didn't use needle bearings. Oilite is a somewhat porous material, and you soak it in oil. They don't last as long as a bearing, but with older materials, clutches didn't last as long either.