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Can i swap a 4.0L I-6, AX-15 tranny and transfer case into a 94 2.5L I-4 will it be direct bolt in or do i have to do anything to make it work.
 

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I've been researching this for the last few days due to the fact that the AX-5 isn't necessarily an offroad transmission and I would like to do a light build on my TJ and this is what I've collected.

The AX-5 is car and light truck transmission closely related to the more durable AX-15 which backed the 4.0. It has been used successfully by jeep to back the 2.5 and also successfully used by Toyota as a car and light truck tranny, therefore: not junk...but not as durable on the trail as its stronger counterpart.

The best two options if not into real hardcore rock crawling would be,
1. The trusty AX-15 which is possibly the best 5 speed manual ever utilized in a Jeep. It also has shown its worth in the Toyota Supra:D.

2. The AX-15's replacement: The NV3550 5 speed manual.

Problem: The 2.5 Liter requires a different bell housing to adapt either transmission. The AX-5 used a 21 spline output shaft, and finally the AX-15 and NV3550 are longer requiring modification of or a custom drive shaft(s).

The 4.0 could also be swapped in, which already is backed by the AX-15 or NV3550, but would require relocation of motor mounts, wiring, new pcm, possible modification of transmission cross member, transfer case, and possibly modification of the drive shafts

I was able to find a whole kit to adapt the NV3550 to the 2.5 including a new transmission. Estimating cost doing the whole thing myself: I'd say in the ball park of 3000+ dollars or 3 re-manufactured AX-5s and 3 centerforce clutches to accompany them. Hmmmmm...mines got 100,000 miles and 9 year on it and still shifts pretty darn good. Also was out on the lot before Mopar +4 fluid, so with synthetic fluid and a tranny cooler, without aggressive driving you're looking at well over 100,000 miles out of a new or re-manufactured AX-5.

http://www.high-impact.net/transmission_and_gear/nv3550_AX5replmt.htm

http://www.novak-adapt.com/knowledge/ax5.htm

and, with a quick search: http://www.pirate4x4.com/forum/showthread.php?t=181361

Best of luck!
 

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No its not a straight bolt in. At the very least, theres fan shroud mods, Motor mounts need to be moved, and drive shafts would probably be differently. On the bright side however, if yoiu get a similar year 4.0L most, if not all of the electrical connections are plug and play. A buddy of mine just did the exact swap, said it was easy as cake if yoiu can weld the new mounts, the rest just went together.

And yes the AX-5 does suck, the fact that it went behind a supra doesn't mean shit. A supra is not a jeep. A 4.0 will most likely eat it up in no time. Remember...the jeep engineers even tho they sometimes fuck things up, they have forgotten more then we could ever hope to learn about forces and the components they choose to put in their vehicles, you didn't see AX-5s behind 6 cyl. engines for a reason.
 

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The original poster isn't gonna try to put an AX-5 behind a 4.0, nor did I say it was ok. He at first was interested in a whole motor/tranny swap, he then asked about an AX-15 behind a 2.5. I shared what I knew. I don't feel I misguided him in anyway.

The AX-15 came behind the supra, which I believe I stated clearly. Maybe I should have stated that the AX-15 counterpart, the R154, backed a 220 hp 3.0 liter Turbocharged Engine which is known for its performance, high horsepower capacity, and reliability. I was attempting to show that the AX-15 is a very good transmission. The AX-5 would be slaughtered in a Supra, however lets take into consideration the low output numbers of the 2.5.

Now, the original VW Beetle had a 24 hp aircooled motor. Its 4 speed manual transmission was "junk"...however my friends 1973 beetle has the original trans with 475,000 miles on it. There's applications for everything. Is the AX-5 all bad for daily driving and mild offroading? No. Would I much rather have a AX-15 or NV3550? Yes.

Eh, the way I look at it. If car companies didn't cut corners to save money, there wouldn't be any modification to be done. Being a Jeep owner is about overcoming obstacles, and employing ingenuity.

Where are you in Southeastern Ct.? I'm at URI. My jeep is bone stock, but one of these days it'll be up to par haha. Always nice to have someone to wheel with. There's a nice trail in southeastern Ct. that starts in Arcadia off of Old Voluntown Road. Ever been?
 
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