Engine/tranny swap

[ekulrenlig]

I am in need of a tranny for my MJ (AX-5). I found a 4cyl 89 YJ engine, tranny, and transfer case for sale.

 

First of all, could these swap into my MJ? Or at least will the tranny replace mine (except for the small clocking difference of the t-case?)?

 

Would it be better to swap in everything together, or just swap the tranny? I am confident of my t-case and engine, but this engine has about 40,000 less miles.

 

Is there anything I should ask the seller about, or look out for, or see if it is included in the sale?

[mjeff87]

If it's TBI like your 87, it's plug and play, with the exception of the TC clocking that you mentioned. Also, the TC shift assembly is different than the XJ/MJ. You'll need to reuse the tranny bracket off your old setup, or better yet, swap the YJ shifter in completely. It's a better design, in that it doesn't attach to the body.

 

Jeff

[Eagle]

You'll need to reuse the tranny bracket off your old setup, or better yet, swap the YJ shifter in completely. It's a better design, in that it doesn't attach to the body.

Only problem is ... it doesn't fit. To run in 2WD you'll have to chop the top off the t-case shift lever, and you'll have to carve away a significant chunk of the tranny tunnel around the transfer case shifter to allow it to come up through the floor. The previous owner of my '88 MJ did it, and if I could find him I'd probably shoot him. There is simply no neat way to do this. It's fine if you just want a trail beater, don't mind a lot of engine and road noise, and welcome the occasional bath when fording or driving in heavy rain. If you actually want a REAL TRUCK, that you can use for things like driving on the street, that ain't the way to go.

 

I can post pics if you need them, but it'll take awhile to uncover the carnage and take them.

[Pete M]

And you'll probably want to reuse the transmission shifter from your truck. I know the TJ one is waaay different so I assume the YJ one would be too.

[mjeff87]

True, true...I didn't mention that part of it. But you can't deny it's a better setup, definately feels more confident when you shift. Every time I shift the MJ, I keep thinking about the whole abomination of parts moving under the tranny tunnel, just waiting to break :D

[Pete M]

Feels like I'm shifting a big rig. :D It's not for everyone.

[ekulrenlig]

Only problem is ... it doesn't fit. To run in 2WD you'll have to chop the top off the t-case shift lever, and you'll have to carve away a significant chunk of the tranny tunnel around the transfer case shifter to allow it to come up through the floor.

 

So basically if I use a tranny from a YJ or TJ it will be a PITA?

Am I better off finding one from and XJ or MJ?

[mjeff87]

No, the tranny fits just fine. But to run the YJ/TJ TC shifter assembly, you've got to do some cutting. The XJ/MJ shifter assembly bolts up the same way, so you can reuse it if you want.

 

Sorry, didn't mean to confuse you there ;)

 

If you get a chance to see the drivetrain combo still intact inside the donor YJ, you'll see what we're talking about regarding how the shift assemblies are different. The only thing that'll be not the same is that the TC will be clocked closer to the floorboard than it used to be.

 

Jeff

[ekulrenlig]

So I can just use my TC shifter assembly and transmission shifter on the YJ tranny without any modifications? The only modification I might have to worry about is the floorboard from the TC clocking?

 

I just found another engine and tranny setup from a 91 Wrangler with the 2.5L, with around 140,000 miles. Will this setup fit in my MJ as well? Apparently either the tranny or engine has been rebuilt, but the seller doesn't know which one. How much do you think this setup is worth paying for?

[mjeff87]

So I can just use my TC shifter assembly and transmission shifter on the YJ tranny without any modifications? The only modification I might have to worry about is the floorboard from the TC clocking?

 

yep

 

I just found another engine and tranny setup from a 91 Wrangler with the 2.5L, with around 140,000 miles. Will this setup fit in my MJ as well?

 

'90+ 2.5L's went to MPI, so you'll need the wiring harness and ECU to swap into yours if you do a complete swap. Or you could just use the engine less the intake and reuse your intake/TBI setup

 

Apparently either the tranny or engine has been rebuilt, but the seller doesn't know which one.

 

that would make me a bit leary about buying..... :roll:

 

How much do you think this setup is worth paying for?

 

I'd say $250-300, but I'm a tightwad ;) If you're engine and TC are in decent shape, I'd probably just swap trannies and be done with it.

 

Jeff[/b]

[Eagle]

So I can just use my TC shifter assembly and transmission shifter on the YJ tranny without any modifications? The only modification I might have to worry about is the floorboard from the TC clocking?

It's the transfer case shifter that's the issue. Use an XJ/MJ t-case shifter. The YJ transmission shifter works just fine (that's what's in my MJ) but it looks idiotic, because it's a lot straighter than the XJ/MJ shifter and sticks up a lot higher. I'm going to change mine to an XJ shifter when I convert the t-case shifter back to what it should be so I can repair the floor.

 

The t-case clocking may not cause any interference with the floor/tunnel at all, or you might just need a few taps with a body hammer. It's nothing to worry about.

[ekulrenlig]

Thanks guys for all the info.

 

So what range of years in Wranglers will have swapable trannies with my AX-5, without having to modify a whole lot?

 

 

BTW--The 91 engine/tranny setup I mentioned earlier is sold, along with a t-case that needs a chain and an almost new radiator for $300. You guys didn't answer my questions fast enough. Haha. ;)