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Trail rig swap: XJ to MJ


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I've got a 1998 XJ that I've owned for almost three years. Started with a mild little budget boost lift and as I got into wheeling more and more, I just decided that it isn't smart to wheel my DD. The '98 still has a lot of life left and is what I want in a daily driver. So it's time to take it back to stock and swap what I can onto my new MJ and sell the rest to recoup costs.

 

Cherokee specs: 1998 Cherokee, 4.0L, AX-15, NP231, Dana 30, Chry 8.25, both geared to 4.56 with a Detroit in the rear.

 

bigdogsicebreaker200705jb1.jpg

 

MJ specs: 1988 Comanche, 4.0L, Puke goat, NP231, Dana 30, Dana 35, 3.07s open open.

 

s7000377largekw7.jpg

 

So here's the plan so far...

 

I'm going to swap the Cherokee's axles onto the Comanche, bringing it spring over. I'll leave the stock springs, add the shackle and it should even out. If its not even, I'm going to add a leaf to the rears.

 

I'm going to take the Dana 30 out of the Comanche and a junkyard (looks to be nearly new, still has glossy stock paint on it) Dana 35 and put it into the Cherokee with stock springs, control arms, and shocks.

 

The front lift springs are 3.5", with a 2" spacer, longer control arms that fit the lift, tie rod, some skids that will fit it. I may reuse the bumper, or sell it and get some 2x4 steel and make my own.

 

Purchased the MJ yesterday and I'm renting some space with a buddy in a big garage. First step is getting the MJ there, pulling at least the front axle, taking the XJ to another garage with a lift and putting the MJ Dana 30 and junkyard Dana 35 on it, with the stock suspension so I can daily drive it again.

 

I'm undecided about what to do with the MJ's bed. It is a longbed and I'm considering removing it, cutting the frame from the shackle back and tubing some of it. The kind of wheeling we do, the bed is going to get pretty messed up in tight turns around trees. It's probably going to get repainted, maybe OD green. Rockers and skids underneith are a priority.

 

I want to make the September Big Dogs at Gore, VA with this thing... About two months to get it totally done.

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You do know that a XJ axles spring perches are the wrong width to just bolt into a MJ. I like the sounds of the project, but I would swap in a 8.8 before i swapped in a d35.. thats just me.

 

Since you are in VA and not too far away (3 or so hours) I make custom mj stuff in my driveway.. you can come on out anytime and get good work cheap since you are one of the few lwb ones that will be around for me to make templates off of

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I'm near Frederick, MD but if I needed parts you aren't that far!

 

pingpong: I'm putting a Chry 8.25 in the rear, not a D35. The D35 is going into the XJ.

 

Is the Dana 30 going to be a problem too, or just the 8.25?

 

I'm going to be reusing the MJ's rear spring, so shouldn't it be fine?

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Its not the springs in the MJ its that they sit in a diff location so you have to move the perches on the XJ axle to bolt it up correctly. But the front should be ok as long as you stay around 33s with it. and the 8 1/4 is better then a D35 but for the work i would buy a 8.8.. But thats me

 

Cole

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Just the 8.25. As for the perches you can buy new ones from the dealer or from the auto parts store for less then 15 bucks.

 

 

The d30 should bolt right in... just be advised to attatch the UCa's first then the Lca's... I have found that to be the easiest way

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Good stuff. We'll MIG the new perches on after lining it up. No big deal.

 

The 8.25 has 29 spline shafts and I think it'll hold up fine to 33s/34s.

 

While the 30 is open it should be okay too, but I don't know how long I'll leave it like that.

 

pingpong: Will the MJ LCAs fit the XJ?

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Good stuff. We'll MIG the new perches on after lining it up. No big deal.

 

The 8.25 has 29 spline shafts and I think it'll hold up fine to 33s/34s.

 

While the 30 is open it should be okay too, but I don't know how long I'll leave it like that.

 

pingpong: Will the MJ LCAs fit the XJ?

d44 only has a 8.5" ring gear and a few more splines so its not that much beefier... your axle should be fine.

 

the d30 is pretty stout little axle, and yours should have the 297 u-joints, it should be fine, it all depends on your drivin style. but you could get a super30 cromolly kit for it

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45.75" on the XJ and 45.25" on the MJ for the perches... is that really enough to have to move them? I've got big long shackles and am only worried about standing up on the trail, no road driving.

 

Can you double check the measurements? I get ~44.25 on my 90 MJ. Regardless, I can remember 2 guys that bolted an XJ axle up to their MJs and both of them eventually had bushing failure on one side and the axle shifted over when at rest and would wiggle a lot under the truck when moving. Also, spring wrap can be a concern and nows the time to think about longer beefier perches and maybe adding an extra leaf the the pack (I added an extra MJ main to my 88 and in the next iteration I'll be adding an Explorer main leaf). The extra leaf should go in right under the current main.

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Before I start all the swapping and everything money will constrain me for a few weeks (moving, vacation, other expenses related to the two)...

 

So It'll be getting painted first. I can't stand the color so it'll be getting a new coat.

 

I'm thinking OD green, black or dark blue...

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you'll have to use the comanche stock rear springs, as the cherokee ones are too short.

 

as pingpong said, new perches are needed as width is different.

 

furthermore, your theory on leaving the front stock and the back spring-over, is wrong. if you spring over the rear on a comanche, you gain 5.5 to 6.5" depending on axle (more or less also depending).

 

that means you will have to have front springs to match the rear, rather than shackles to match the front.

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The front lift springs are 3.5", with a 2" spacer, longer control arms that fit the lift, tie rod

 

The XJ is lifted like 5.5 inches in the front... did ya miss that? :D

 

That suspension is going on the MJ...

 

???

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I just swapped axles out of a cherokee into my MJ. The 30 was a bolt in. The 8.8 that was out of the XJ had to have the spring perches moved. If you don't weld it doesn't cos tmuch to have it done. Mine has 5-6" of lift upfront and SO rear and seems to be level so far (haven't had it out yet).

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that suspension better have new control arms. and you may end up needing an extra inch of lift up front to level it out.

 

spacers suck

 

The front lift springs are 3.5", with a 2" spacer, longer control arms that fit the lift, tie rod

 

Why do you think spacers suck? They'll work absolutely fine for this application. I'm not using blocks...

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The plan sounds good to me, minus the perches deal. I don't understand why there's so much negativity in this thread.

 

Selling your current bumper could definitely make you some coin, and even with the price of steel, building a bumper is pretty dang cheap.

 

Unless the MJ leaves are real saggy, the SOA should be level with 5.5" of front lift, maybe even a little bit high.

 

And finally, if you wheel tight corners in trees, you can kiss your taillights good bye, and replacements, for most of us, are hard to come by. Selling the bed/tailgate/taillights might be a good choice for you. I know alot of people on this board need all 3 of those things, and you'll end up destroying them.

 

Keep on keeping on!

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Removing the bed has it own set of problems to deal with :brows: I am not trying to be negative, but I want him to think about it before he goes full bore into it.

 

How are you going to mount your fuel tank?

 

How are you going to mount your tail lights?

 

Are you going to be able to reamin street legal?

 

 

In my personal opinion I say everyone should cut the frame and have some tube bent and call it good :D

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I'm not even titling it, it's never going to see a paved road, EVER. It doesn't need to be street legal.

 

Like I said before, if we bolt up the rear and they're not right, I'll just weld in new perches... It's like $20 + 15 minutes on the MIG.

 

I'm going to be selling the tail lights and the tail gate. If anyone needs them let me know. I'm cutting the bed at the rear shackle mounts, since all that from the rear back is going to do is mash trees. Decided to keep the bed on for now.

 

I'm probably going to sell the bumper and the winch and build a new bumper out of 2x4. I don't really need a winch right now for the kind of stuff I'm going to be doing.

 

It's short armed so the 3.5" coils and spacers are fine...

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Keep the winch... You can always use it :brows: The front bumper will transfer over as well. Keep it too. Much easier to keep what you got then buy new.

 

I think your plan is solid... I say remove the whole bed and sell it.. then look at making your own flatbed. The sale of the bed and other crap should pay for the materials needed to make a flat bed

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