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Motor/Trans/Tcase Question


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Now would my best bet be to buy a donor XJ and swap the motor/trans and t case along with front axle?

 

I understand ill have to buy/swap other parts but for my major parts will those work?

 

Currently have a 2.5, 4 spd, 2wd

 

was thinking 4.0, ax-15, 231.

 

Any insight would be great. I have been currently reading up on different options and figured any help/links I get would be great.

 

Thanks!

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If possible it's always better to get a complete donor.You can check everything out and make sure it's working that way. No matter how careful you are if you buy just the parts you think you need, you always forget something. Another trip back to the JY. You can sell parts you don't need.

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I wouldn't plan on using the axles from a 4.0/stick. they will have 3.07s. your current rear should have 3.55s, so you can keep that and grab a front from a 4.0/auto XJ from the junkyard. easy. :D

 

to swap to a 4.0 you will need to change pretty much everything, harness and all. a good running donor is the way to go.

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Yeah I assumed the harness would be in the swap, the dash will be to since I need one of those. I also would be regearing/rebuilding the axles to so it wouldn't be a big deal. (big deal in amount of work but already getting done)

 

Now it wouldn't matter the year of the XJ correct?

 

Thanks for the confirmation!

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Now would my best bet be to buy a donor XJ and swap the motor/trans and t case along with front axle?

 

I understand ill have to buy/swap other parts but for my major parts will those work?

 

Currently have a 2.5, 4 spd, 2wd

 

was thinking 4.0, ax-15, 231.

 

Any insight would be great. I have been currently reading up on different options and figured any help/links I get would be great.

 

Thanks!

 

What year MJ do you have?

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I would not regear or rebuild the axles unless you have a cheap line on the parts and know what you're doing. Swapping in an entire axle with the gears you want is much cheaper and they are plentiful. Also try to find something better than a D35 for the rear. 97 and newer Chrysler 8.25" out of an XJ are a great upgrade, plentiful in junk yards end it is relatively simple and cheap to cut off the perches and shock mounts and have new perches welded on.

 

I would get a similar year (to your MJ) parts XJ for everything except the axles. Get the axles (both) from a 97-99 4.0/auto with an 8.25" in the rear, as that would get you best combination in parts for both the front and back.

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Rebuilding the axles wouldn't be an issue as I would do them my self. My MJ is a 88, would swapping everything from a 97-99 not work?

 

I'd hate to buy a donor and stuff have to go buy axles again. Although I have a 8.25 and rebuild kit in my garage. Just needs a gears set and cover which wouldn't be an issue of I am upgrading the gears and cover.

 

So what year would be best for me for the 4.0/ax15/231 combo since I have the rear axle already.

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To keep the electronics plug and play and not have to splice Chrysler stuff into Renix stuff you should stick with 87-90 (91?) for the parts truck.

 

Reason I said 97-99 for the axles is because the front would still be high pinion (86 through 99) but give you the single piece passenger side shaft without the central axle disconnect (92 and newer? Or any year with Selec-Trac) and also gets you the larger stronger u joints (95 and newer or any year with ABS). It also gives you the 29 spline 8.25" (late 96 through 01) which is about equal to a D44 whereas the earlier 27 splines ones have shafts nearly as thin as a D35.

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Ok, to back up a bit. Is there a good combo of tranny/tcase I can just swap into the comanche? I'm unsure of what transmissions will bolt to the 2.5.

 

I'm gonna have a tough time finding a small year gap with all the options I want as a donor, am I not?

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Ok, to back up a bit. Is there a good combo of tranny/tcase I can just swap into the comanche? I'm unsure of what transmissions will bolt to the 2.5.

 

I'm gonna have a tough time finding a small year gap with all the options I want as a donor, am I not?

I don't know. Have you given us the year of your Comanche yet or am I missing something?

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Ok, to back up a bit. Is there a good combo of tranny/tcase I can just swap into the comanche? I'm unsure of what transmissions will bolt to the 2.5.

 

I'm gonna have a tough time finding a small year gap with all the options I want as a donor, am I not?

I don't know. Have you given us the year of your Comanche yet or am I missing something?

 

Your missing it, lol it is a 1988 2.5l 2wd ax4

 

I'm just looking for best/smartest option before I spend money on something I don't need. (and I'm doing a lot of reading too)

 

Plus this build is replacing my d60 swap the XJ was going to have. That will be next. :)

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I just finish a simular project on my MJ... You can read all about here: http://comancheclub.com/forums/viewtopi ... =7&t=33558

 

Hope you get some pointers from my thread, if not, ill do my best to help you in anyway. Bottom line, it was an easy project.... T :thwak:

 

 

Cool I'll check it out when I get to my laptop!

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Finding a 4.0 litre 4wd automatic Cherokee for a parts rig is easy, as there are a million of them. Finding one with a manual transmission will be a bit harder.

 

Replacing a 2.5 with a 4.0 is quite a bit of work, though. Pop the hood on any 4.0 Cherokee or Comanche and notice all the differences between it and your 2.5. If you can find a 2.5 manual 4wd Cherokee (any year) you can swap the transmission and transfer case and related parts and keep your current engine.

 

The only manual transmissions that bolt up to the 2.5 are the AX4 and AX5 (which is the same as an AX4 plus one additional gear. Everything inside (except for 5th gear) interchanges). The much stronger AX15 could bolt up to it if you can find the holy grail of bellhousings out of a 2.5/AX15 Dakota. I think there's only one out there and someone on here already has it.

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Mine goal is to run 33's and be happy with that. I'm going to do the bigger stuff to the XJ.

 

I just want to be able to play a little with the MJ and still drive it daily if I chose too. I will just read, and search for parts. I will end up choosing one when I find the right deal. I'm not afraid of the work, as long as I am getting a nice solid package out of the deal.

 

I will be searching for this dodge dakota tho :typing: lol

 

Was I miss informed when I was told the ax4 is known for gernading?

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The AX4 and AX5 are fine behind a 2.5. The biggest problem is with people adding gear oil which contains sulphur which eats the synchros. 10W30 works way better.

 

But I don't think you'll be happy with a 2.5 pushing 33" tires unless you move to at least 4.10 gears.

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The AX4 and AX5 are fine behind a 2.5. The biggest problem is with people adding gear oil which contains sulphur which eats the synchros. 10W30 works way better.

 

But I don't think you'll be happy with a 2.5 pushing 33" tires unless you move to at least 4.10 gears.

 

 

I will be regearing to atleast 4.56's I have those new for the d30 now, and can get them for which ever rear I go with. Also I do have a aw4 and 231, will that bolt right up? (just weighting my options I do wanna keep the manual tho)

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What the AW4 bolts up to depends on what it was on. If it came off a 4.0 (most likely as almost all 2.5s have a manual behind it), it will only bolt up to a 4.0. As for the 231 transfer case, it came with different input shafts depending on what transmission it sat behind, and sometimes with the same transmission there is a difference in what year. I would go with 4.0/AW4/231 combo for the simple reason it is the most common combination out there and thus the easiest to find a donor for.

 

Again, if you go from a 2.5 to a 4.0 having an entire parts vehicle (XJ Cherokee works for everything except rear driveshaft) is a must because there are a LOT of little parts and parts you wouldn't even think of that need changed over: transmission cross member, engine mounts, radiator support, little bracket in transmission tunnel for the transfer case shifter, stuff like that. Staying with the 2.5 is less work, but still there are a number of little detail parts you'll need.

 

I converted a 96 4.0/AW4/2wd Cherokee to 4wd using a 96 4.0/AW4/4wd Cherokee as a donor. After I had stripped the donor I was expecting to do it in a weekend: take 2wd stuff off Saturday, install 4wd stuff Sunday. It ended up taking all weekend to remove the 2wd stuff and gut the interior (seats and carpet) to have the needed access to the steel floor, then 5 evenings to install the 4wd stuff and all day the second Saturday to put the car back together again. I have a pinched wire somewhere shorting out because now when I turn on the lights the fuse for the dash lights blows immediately. It was fine for about a month after the swap. Haven't had the gumption to try and find it yet, though.

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Ok. well I'm not going to cut corners. Thanks for your input marcel, I value what you say! I will look for a donor XJ. between 88-90 with the 4.0/aw4/231 combo. I'm still picking up this other aw4/231j that came out of a 95 I think the guy said. They might just get sold or be ready for the XJ since its has the aw4/242 right now.

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  • 1 month later...

So I found a auto trans and tcase from a 88 MJ, does anyone know what else would be needed to change my ax4 over? I want to pick these parts up but I would also like to know what else I would need to get in case these people have it. It will be almost a two hours drive so I don't want to go back if I don't have to.

 

They also have a d30 non disco jamminz.gif

 

 

Edit: With the dakota bell housing what year would it be from, and what year ax15 would I need to find to work with my set up?

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