98 TJ engine swap: automatic to manual transmission

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Jms76

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Hello-
Searched multiple forums and topics, but been unable to find answer.

Looking for a little help or guidance.

Purchasing a used good low mileage in-line 6 engine out of a 1996 Cherokee with an automatic transmission.

Going to install it into my 1998 Wrangler which has the in-line 6, but has a manual transmission.

Plan to keep the manual transmission, is there any mounting issues or other issues using an engine that had an automatic transmission mounted to it. See reference to a pilot bearing, but not sure if that is an issue, relevant or show stopper?

Any help would be appreciated.
 
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You’d be smart to pick a different 4.0 and not the one out of that 96 XJ. You’re about to find out that you’re making things much more complicated than they need to be.
 
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Chris said:
You’d be smart to pick a different 4.0 and not the one out of that 96 XJ. You’re about to find out that you’re making things much more complicated than they need to be.
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Sorry, could you elaborate a little more. Engine is a long block and per cross reference it should be the same.
 
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Chris said:
You’d be smart to pick a different 4.0 and not the one out of that 96 XJ. You’re about to find out that you’re making things much more complicated than they need to be.
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Chris said:
I know very little about this.
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Your post and Jerry's like made it sound like you guys knew something specific.

To the best of my knowledge, earlier 4.0's (both of these are in my book) don't have the big casting differences in the block or the head you can run in to with the later years. They also didn't make different versions for different platforms like they did later on. There is no distributorless ignition to worry about. Engine accessories should all be in the same location. Any issues you would run in to should easily be solved by swapping a few parts I believe. I'll caveat all that with saying I haven't done that specific swap.
 
I'm not sure about the 96 4.0, but I know the 99-2000 xj engines are different. the bosses in the block for all the brackets are in different locations.
 
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Appreciate all the feedback and insights. Hopefully after a few more weigh in, I’ll know with more certainty that this will work. The engine that I’m looking at as a donor is out of the 96 Cherokee, but was rebuilt by jasper probably sometime around 2005/6. Spoke to jasper today, they don’t have a record for it - they only keep records at least accessible in the system for 10 years. Have the jasper number, just couldn’t look it up. Imagine original engine failed out of warranty period, so probably replaced around the timeframe mentioned above. I’m not sure if a rebuilt engine changes anything, but wanted to make sure that was known as well - just in case for some reason it matters. Thanks again.
 
Here are the items I’ve identified that would need changed.
1. Remove bushing/sleeve from back of crank, replace with adapter bushing and pilot bearing. Not even sure an automatic transmission has any bushing/sleeve, just maybe crank has a large diameter hole that requires a bushing and pilot bearing.
2. Remove 90 degree oil filter elbow.

so far, that is all I’m seeing.
 
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I don't see any foreseeable problems. A 96 XJ engine might have the hole in the head for the coolant sender if it was back in the days before Jeep went to the thermostat housing sensor supplying all info to the PCM and the PCM feeding the gauge. Those older Jeeps had a sending unit in the head for the gauge only, and still had the sensor in the thermostat housing which was for the PCM. This might be the case since 96 was an odd year in that it used the old SCI gauge system yet integrated in OBDII. Anyways, worst case just put a dummy sending unit to fill the hole and just leave it unplugged since your TJ would have nothing to plug in there. If no hole, nothing to even think about.

The blocks from 91-99ish are all interchangeable. Somewhere around 99-2000 started the new block with new accessories. The only exception in all of that is the 91 used a different pilot bearing hole in its crank but you are not looking at an engine out of a 91 so it doesn't matter. Strip the engine down to just a long block, swap your stuff on, it should be good to go in pretty much every way.

Yes, a wrangler does not need the 90 degree oil filter adapter elbow, so you can ditch that. Cherokees needed it for their unibody construction.
 
Chris said:
You’d be smart to pick a different 4.0 and not the one out of that 96 XJ. You’re about to find out that you’re making things much more complicated than they need to be.
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Chris, blanket statements like this make it sound like you did the swap and know for sure that the process will be riddled with problems (which it will not be for this guy). A 96 XJ to a 98 TJ should be absolutely no issue. If he had a 2000+ TJ, yes, not really an option because the older engine would not support the newer ignition system coil rail (nor the vastly different accessories, later style water pump, intake manifold, etc), but on a 98 TJ, no. They are virtually the same engine at the core with the same block bosses.

The only difference is the Cherokee uses a few different accessories and so they have a different layout and design, but they follow the same bolt holes, water pump holes, etc. so his TJ components will all bolt up.
 
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Jms76 said:
Here are the items I’ve identified that would need changed.
1. Remove bushing/sleeve from back of crank, replace with adapter bushing and pilot bearing. Not even sure an automatic transmission has any bushing/sleeve, just maybe crank has a large diameter hole that requires a bushing and pilot bearing.
2. Remove 90 degree oil filter elbow.

so far, that is all I’m seeing.
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Can you elaborate on #1? I'm guessing by adapter bushing, whoever said this is talking about the donut the pilot bearing fits into from the factory? If so, a new Mopar pilot bearing will come with both, assembled to each other. And as you said, I am not even sure that the AW4 would have anything in the back of the crankshaft to begin with since the torque converter is floating on the flexplate and trans shaft at that location. That would just be something to field evaluate when you dig that far into it, but certainly should be no issue to install your new pilot bearing into in order to bolt up the AX15.
 
As for # 1, I’m not sure if an automatic transmission has anything that has to adapt to the hole in the crank.

Based on your comments, don’t think so.

but this I’ll need to use this item rather than just the pilot bearing.

EDE811B8-0FE7-408E-A400-A16B4F20D420.jpeg
 
Jms76 said:
As for # 1, I’m not sure if an automatic transmission has anything that has to adapt to the hole in the crank.

Based on your comments, don’t think so.

but this I’ll need to use this item rather than just the pilot bearing.

View attachment 277067
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The Mopar pilot bearing you would get at the dealer will be that whole assembly, both bearing and sleeve. That big donut thing the bearing portion is installed into will fit into the crank, assuming there is nothing from the XJ engine needing to be removed (sleeve or whatever that other advice was talking about if there is anything).

The only advice I have on that is to not hammer the damn thing in too far into the crank. Otherwise it will be almost impossible to get that adapter out someday. Hammer it in until it's flush with the crank and then stop.
 
SkylinesSuck said:
Yup, just install the pilot bearing into the crank out of the '96. No biggy. But it does need doing.
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Yeah, I think the bigger question was if there will be anything in the back of the 96 crank from the auto transmission. A sleeve or something, from when he said something he needs to do will be “remove sleeve/bushing from back of crank”….but I just can’t think of what would be there or why. Guess he’ll see when it’s opened up.
 
Not sure, never dealt with a automatic 4.0 crank, but it won't be a big deal to remove and replace even if there is a bushing or something there.
 
My biggest concern is having to drill anything on the block or heads. Especially any drilling on the crank. I’d rather buy a fully rebuilt engine than having to drill or modify engine mounting. Didn’t think I’d be going down this engine change path, but learning quite a bit in the process. Sounds like I should be good, other than a couple of minor items. I’ll provide an update once I get into it.
 
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