Swapping In A 4.0/5 Speed

[TheDude]

I really want an MJ but, I'm having a hell of a time finding one with a 4.0 and a AX-15.

 

So, I was thinking of getting one with the 4 banger and swapping in a 4.0 (ideally an H.O.)or maybe find one with the 4.0 and swap in an AX-15. which would be easier?

How hard would this be? and what exactly will I need? Should I go for pre 96 or post?

 

I know I'll need a 87 or later.

 

I was also contemplating doing the entire 97+ swap interior, engine, and computer. But, I'm concerned how difficult that may be.

 

Thanks in advance!

[MancheKid86]

find a 4.0L an put the ax 15 in, need pb74 (input shaft pilot bushing) and its a direct swap,

 

swapping in a 4.0L is alot work, all new components, harness, computer, welding new motor mounts,

 

if your doing the 97 int. swap, why not do the whole conversion?

[onlyinajeep726]

find a 4.0L an put the ax 15 in, need pb74 (input shaft pilot bushing) and its a direct swap,

 

swapping in a 4.0L is alot work, all new components, harness, computer, welding new motor mounts,

 

if your doing the 97 int. swap, why not do the whole conversion?

 

I'm not sure what you mean with this.  All that's needed there to swap from a 2.5 to a 4.0 is the driverside frame rail mount from a 4.0 equipped MJ/XJ.  Simple unbolt/bolt back procedure lol.  But as you said, everything else will need to be changed, including dash harness.

[87Warrior]

If you are swaping in a HO 4.0/ax15 in place of a TBI 2.5, you will have to do the engine harness, dash and harness, frame motor mounts (bolt in) and radiator support. It is essentially the same type of work as the 97+ swap, just everything bolts in place as it should.

[TheDude]

So the driveshafts will still fit too? That's one of my concerns if trying to figure out what shafts I'll need.

[87Warrior]

So the driveshafts will still fit too? That's one of my concerns if trying to figure out what shafts I'll need.

 The rear will need shortened. For the front, I would find one from an XJ with the same drivetrain as you are swapping in.

 

.....in fact, you would be money ahead to buy a parts XJ with the drivetrain you want to do the swap. That way all of the individual pieces don't nickle-and-dime you to death.

[jimoshel]

:agree: It's the only way.

[TheDude]

Ok, say I find an mj with the 4.0l but its an automatic.

All I would need is the trans, transfer case, and both driveshafts?

I found a guy parting out a 96 xj with a 5 speed. Would this year work, or does it have to be older?

[FrankTheDog]

Yes it'll work. you'll want the master and slave assembly.

Transmission and transfer case, crossmember, transfer case linkage.

Front drive shaft, the rear drive shaft from the auto MJ will be the right length with the 96 XJ rear driveshaft slip yoke on the AX15.

Especially if it was originally a Dana 35 and you put in a D44. A D44 auto drive shaft will be tight on a D44 but just right on a D35.

You'll need to get a pilot bushing for a 73 AMC V8 with a 3 speed. Unless you buy a 92.

Might need the pedal assembly too, not positive on that. Grab it while you can. Unless it's a 91-92.

[BookspanS]

Will doing a 98+ swap work on an 86 MJ?

[streetjeep2.5]

Not wanting to hijack the thread, but thinking of swapping in a 4.0 in my 87 2.5 (Renix) 4x2 4 speed. I know the basics are engine and trans, radiator and support, frame mounts, trans cross member and mount, drive shaft (D35), and all the wiring.  But, for ease of swapping, what years would be the best to look for?  I know it may sound silly, but if I was to abandon FI and computer in favor of aftermarket intake and carburation only because it makes things easier to work with (fewer "sensors" etc) would this change what engine to look for?

[a1awind]

soo....lemmie throw in a question here....

i want to swap in a 4.0....it HAS TO be the cheapest way/easiest way  possible.

would finding a renix 4.0 cherokee/mj donor be the easiest way of doing this? i am trying to avoid the nightmare of a rewire.

and ultimately ending up with a partially dissasembled comanche permanently occupying my garage.

 

[onlyinajeep726]

You'll have to swap the wiring harness and ECU if going from a 2.5 to the 4.0.  There's no way around that, unfortunately.  But luckily, everything will fall into place so to speak since the engine bay for a 2.5 and 4.0 is the same.