XJ/MJ Concerns

[detailbarn]

Ok I will try to keep this short but no promises. About a year ago my wife and I decided that we wanted two similar vehicles that would last us a very long time , our hope was to not have to replace them unless they where stolen or damaged in a accident. Our requirements where , classic looks , DIY friendly strong reliable engine/drivetrain , solid axles front and rear, four doors for her two for me. So after searching for about six months we decided our vehicles would be a 2000 Jeep Cherokee for her and a 1989 Jeep Comanche for myself. The Comanche would be a more involved project a ground up rebuild including updating the sheet metal to 2000 pieces as well the complete drive train would updated to new pieces. So while I'm building this I purchased a left over 2006 Unlimited Wrangler to be my daily driver. work truck.

So I purchased a 2000 Cherokee with 100,000 miles on that was extremely clean it was previously owned by a navy officer who used it to commute between bases so it was never abused. I stared the minor mods we where planning on the Cherokee which include a OME lift w 245/65 BFG AT' a Dana 44 rear with ARB locker , ARB Bull Bar, rear bumper with tire carrier and a set of Detours off road slider - unibody stiffeners.

Before starting these mods I wanted to make sure the truck was in all around good order which it is , a few very minor items need attention nothing major. One of the small items is the drivers door hinge is toast , not pulling away from body rather just worn out from alot of opening and closing. No problem body shop is going to take care of it for $250.

Ok here's where my concerns come in , after reading a few things online and speaking to a few body shop guys I'm under the impression that the unibody on the Cherokee will with out a doubt ultimately fail even under normal use. My plan included unibody stiffeners which I thought would help eliminate any unibody problems , now I'm being told these will only make it worse. I've been told that the unibody will fail at the A pillar , effectively bending down and destroying the truck. This is under normal use meaning a grocery getter , I plan to use this truck for my wifes daily driver and a family camping rig that will see regular use on an off road. Nothing major but certainly above average use.

The only fix I've been offered is to cage the truck , which really isn't something I want to do. So here is my dilemma if this is true then these are not the long term trucks I was planning on building so I would rather get out of them now rather than put any more time or money into them. If this is inaccurate then great , I just need to get a definitive answer because I plan to have these trucks for a minimum of 20 years. Thanks for reading my unbelievably long post , and any help anyone can provide is much appreciated.

[2006KJSPORT4x4]

To be honest this is the very first time i've heard of a cherokee or any otehr unibody jeep having such a failure at the A-pillar. I know people from L.O.S.T. KJs that wheel XJs, ZJs and KJs. I have never heard any complaints of structural concerns at the a-pillar. Most of the guys on the board wheel hard core stuff out there in Cali and I have never heard complaints about any premature "warpage" if you will at the a-pillars or of the unibody structure at all. In fact the only time i've had to mention warpage of the KJ was when I totaled my first one and the chassis actually twisted and none of the doors would shut on it, not even the rear glass.

My friend here in Memphis too has a 94 Cherokee, has had a lift and wheeled and driven his over 200K miles and has no such bending or lining up issues to report about.

All in all I think that something more catastophic then the bending at the a-pillars, if that does happen, will occur first before you have to worry about the a-pillar issue.

That is just my .02.....

[cshontz]

The longevity of an XJ unibody is usually a non-issue. I would not expect failure at any point during the normal life of the vehicle - even with minor modifications and moderate off-highway use.

I think Sven (xxxpedition) just retired his XJ because of structural issues, but that vehicle was put to extraordinary use.

[detailbarn]

thanks for the reply's, i really thought this sounded far fetched but in the same breath these are the first unibody trucks I have ever owned so I am not that educated on them.

Thanks again and if anyone else has more to add please do.

[XXXpedition]

actually my xj's unibody failed... :-))))

BUT no worries. i took it off-road a lot and i'm talking extreme here. i rolled it twice (each side once) and didn't fix the damage. that by itself compromised the structural integrity of the body immensly. i also carried a roof rack which for expeditions was probably over 400lb. but what killed it in the end was 1000s of miles of heavily corrigated roads through australia.
it had over 250k miles on it.
i know several xjs with that milage and as mine with original engine, tranny and transfer case.
can you ask much more of a vehicle?

to read more about this truck you can visit my site http://www.xxxpedition.com to see its hard life :-))
http://www.xxxpedition.com/Events/2005-MoabSafari/MoabGallery/RollOver/IMG_5499.jpg

[Haggis]

From my own experience with my MJ ('87), I never had any structural problems. When I sold the Comanche in '97, it had almost 290,000 miles on it and except for regular maintenance items the only part I had trouble with and needed to replace was the front track bar ( it was just wore out). My MJ was never babied; it was my daily driver and work truck; hauled firewood, lumber, gravel;trail breaker for timber cruising; mud toy and gypsy camp hauler. I use my truck(s) hard for that's what their for and the MJ never whimpered or whined, even though it was used past it's "capabilites". I don't think you would have any problems unless for a case of extreme bad luck or attack of sudden brain deathitis (sudden loss of common sense). The only reason I sold the MJ was that I had one child in a car seat and another one on the way and there was no fitting two car seats on that notched bench seat. God, I miss that truck.

[Wanderlusty]

A friend of mine has an '87 XJ with 230,000 miles. Still all the original running gear. Still runs well.

I have never heard of structural failure under normal or even with lift and offroading, save for examples such as Sven, who REALLY put that truck through it's paces.

Unless you are planning on loading up and driving round the world....you should be ok...

[OverlandZJ]

Only issues of body/frame fatigue i have seen is on a rockcrawler...and only after years of action. An XJ can and will develop stress cracks at the rear hatch on a 4 door and at the b-pillar vent on a 2 door. MJ's have a regular frame from the back of the cab to the rear bumper and is less likely to develop issues.

My first XJ was a two door, in 00 i rolled it onto it's roof on Guardrail in Tellico, Bent the a-pillars down and the b-pillar was damaged from landing on a boulder as it went over to the pass side. Anyway...i chopped the roof in prep for a cage. Everyone was telling me it'll fold like a Taco, so i scrapped the project idea. I did realize though that with the aftermarket front and rear bumpers and rockrails it strengthened up the unibody signifigantly.I actually wheeled it out back in the woods before i tore it down. Now, it's common for an XJ to be chopped and caged...some are hardly recognized.

I'd share pics but recently my newer laptop crashed and took all my pics with it.

Here is a few pics of the Jeep from a JP article.

http://www.jpmagazine.com/eventcoverage/naxja_xj_fest_2000/

:safari-rig:

[sacto_patrol]

I have owned three XJ's. With two of them being dedicated Rubicon rigs. I never had unibody failure. I did have the upper control arm mounts break three times on me. But that was it. I would not be worried about the unibody at all.

[xr8dxj]

You can always add frame stiffeners and add rock sliders beforehand to fend off unibody failure. However unless you go on a 3 three year multi-continent expedition, odds are the uni-body will serve you fine.

[SeaRubi]

why not build that LJ you got there? :wings:

[LUISJG]

IN 15 years of beeing arround jeeps and xj's never seen or hear about a problem with an xj unichasi.

[detailbarn]

why not build that LJ you got there? :wings:


I'd like to but it doesn't fit the needs of either my wife or myself , well sorta mine but my needs lean more towards a "work" truck to tow my trailer with to run my powerwash company. And though the LJ would work I would feel bad not using it to it potential. So I will be running it for the next few years for work but only so I can build the MJ up.

[\\'anderer]

My 94 XJ has around 160K miles, and so far the only body issue is the drivers door hinge. I would not be concerned with unibody strength, XJ's are tough little boxes.

[Big_Geek]

A friend of mine has an '87 XJ with 230,000 miles. Still all the original running gear. Still runs well.

He's referring to my XJ - still running fine and it has been abused by previous owners. So if mine can hold up to a hard life for almost 20 years, you should have at least ten years left in yours.

I also frequent the NAXJA site and have never heard of someone having this problem. You might run a search there for good measure:

http://www.naxja.org

I have heard of problems with the steering box applying more force to the unibody than it can handle, but most of the good aftermarket bumpers fix this. And, if you want to stay with stock bumpers you can add a frame stiffening plate there that ties into the stock bumper mount location to prevent this problem. From what I understand, this problem is much better to prevent than to try to repair.

Hope this helps.

[riverfever]

I agree. The XJ club I belong to has some guys that run really difficult trails. Many have cages for protecting themselves but there are some that have no "frame" stiffeners or cage work and they are structurally fine. I know Sven had issues with his but that thing lived a spirited life. I've seen one other rig that was tweaked a bit but it also had seen quite a bit. I think you'll be fine.

[Xtreme XJ]

Detail.... so did you go ahead with the XJ/MJ combo ?
My experience with the XJ (a new 96) is I have cracking on I believe 7 out of the 8 pillars.... mostly small, but I still have minor concerns.... I know some day these will become an issue as I continue to wheel.
Mine was a multi-purpose vehicle for 10 years and I've wheeled the piss out of it, I thought it was going to spin in the middle a few times.... but it has held up well.
I also feel I'll be able to locate a decent vehicle in the future to swap parts over if necessary.
I too don't "need" a cage, but if I were to get a new project I might put one towards the top of my list.... rockrails.... chassis stiffeners quite possibly.
The uni-body is probably the only thing I don't like about the XJ... that and it doesn't have a V-8....
You might as stated check out NAXJA and search for pillar cracking or the likes....

Good Luck...
Curt :safari-rig:

[detailbarn]

Detail.... so did you go ahead with the XJ/MJ combo ?
My experience with the XJ (a new 96) is I have cracking on I believe 7 out of the 8 pillars.... mostly small, but I still have minor concerns.... I know some day these will become an issue as I continue to wheel.
Mine was a multi-purpose vehicle for 10 years and I've wheeled the piss out of it, I thought it was going to spin in the middle a few times.... but it has held up well.
I also feel I'll be able to locate a decent vehicle in the future to swap parts over if necessary.
I too don't "need" a cage, but if I were to get a new project I might put one towards the top of my list.... rockrails.... chassis stiffeners quite possibly.
The uni-body is probably the only thing I don't like about the XJ... that and it doesn't have a V-8....
You might as stated check out NAXJA and search for pillar cracking or the likes....

Good Luck...
Curt :safari-rig:


yes i am going with the mj/xj build. my wifes xj has no cracks i myself went over it and also had two mechanics look at it and they found nothing. I honestly feel that my concerns where unmerited or atleast overly hyped. All metal can fatigue unibody or not, there was a recent post here about a bed mount cracking on a members tacoma which is body on frame so it doesn't seem to be a big deal. My 2001 Double Cab Tacoma cracked leafs springs left and right so I think as long as I take care of it add frame stiffeners I'll have these vehicles for at least 25 more years.

[Offroader5]

My XJ is sitting with 8" and 35's and when I wheel it, I wheel it on some difficult trails. It really only sees rocks ie..rock crawling on 3 & 4+ trails (on the 5 scale)....and I have yet to even twist the unibody to the point of it causing any damage. If this happened, the first thing you'd notice is that the doors don't line up anymore. The doors (when closed) add alot of structure to the "frame".

One thing in lieu of the stiffeners...is to install some good sliders. I have a set of sliders I built that go back to the unibody "frame rail" with 4 legs and then they also bolt the entire length of the lower rocker pinch seam with 10 bolts with a piece of small angle welded across these legs. This, I think, has kept the twisting to a minimum. Think about it...the continuous piece along the pinch seam is tieing the whole length of rocker together with the frame rail and keeps it from twisting. It's an option :)

Click the thumbs for big versions:

http://smg.photobucket.com/albums/v126/offroader5/Just%20Some%20Pics%202/th_slider2.jpg (http://img.photobucket.com/albums/v126/offroader5/Just%20Some%20Pics%202/slider2.jpg?t=1181347890) http://smg.photobucket.com/albums/v126/offroader5/Just%20Some%20Pics%202/th_slider5.jpg (http://img.photobucket.com/albums/v126/offroader5/Just%20Some%20Pics%202/slider5.jpg?t=1181347974) http://smg.photobucket.com/albums/v126/offroader5/Just%20Some%20Pics%202/th_slider.jpg (http://img.photobucket.com/albums/v126/offroader5/Just%20Some%20Pics%202/slider.jpg?t=1181348030)

Not only are you stiffening the unibody this way...but you also gain the rocker protection with the slider rail :)

[Alex]

My Cherokee is a 1997 with 170,000 miles and I have had/am having unibody issues. It has been on 33's and wheeled regularly since June of 2001...

http://www.fototime.com/3A5BB7EFF7E3C48/orig.jpg

The first problem is also the most common- the "frame rail" below the steering box develops a crack and the laminated lower sheetmetal layers start to buckle and seperate.

http://www.fototime.com/CD52AFFA0C114DB/standard.jpg
http://www.fototime.com/50B759EB69F18F3/standard.jpg
This seems to be caused by the installation of an aftermarket front bumper for mounting a winch. The Cherokee body in stock form does allow some twisting, the trouble starts when you bolt a highly rigid, heavy front bumper to it. The body still twists, the bumper doesn't. Something has to give. Bolt-on steering box braces excaberate the situation. Use the reinforcing plates that weld or bolt on to the sides of the uniframe.

The next major failure was the leaf spring shackle body mounts.
http://www.fototime.com/D0ACE11E803E3A6/orig.jpg

Fixed like this:
http://www.fototime.com/8DDF56FD355DEBB/orig.jpg

I have been developing cracks where the roof meets the pillars for a while, as well as cracks at the corners of the vents in the door sills. On my last trip I noticed the passanger door no longer contacts the body when closed. On closer inspection, the roof forward of the factory roof rack rails has a downward bow and the floor pan is starting to seperate from the frame rails. Yes, my beloved Cherokee is starting to resemble an old swaybacked horse. I have some T&T frame stiffeners ready to install as a band-aid, unfortunately my fabricator has moved on from his last position.

Keep in mind that my Jeep has lead an unusually tough life. It weighs at least 5000lbs when I leave on a trip and gets wheeled hard. I also put many miles on bad dirt roads, usually at higher speeds than is wise. If I were to start over I would do frame reinforcements first. Here is a good example:

http://www.naxja.org/forum/showthread.php?t=913774

I am probably going to keep on patching my current Cherokee. It is a 2 door, 5-speed, which are very hard to find in the 97-up body style. If a clean one were to appear for sale, that would be another story. This one took 4 months to find so I am not holding my breath.

[detailbarn]

wow most of the post here and naxja have told me my concerns where unmerited but now this last post. personally I thank everyone for their input on my concerns. I have at this time deicided to go with the xj and mj, I own them and the really fit my needs well.

Alex I am shocked to see how bad your xj is , personally I will never push either of my trucks that hard. My opinion is that the way you've used your truck is border line abuse not just normal expedition use. Not a bad thing but something to be expected with a trail rig that gets beat. A friend of mine got similar damage on hi 98 TJ and that was full frame.


So my conclusuon is I will add sliders with frame stiffeners and gusset or support any other area I think needs it during my build. I plan on using ARB bumpers for both vehicles and the MJ with have a snow plow too the front will be boxed nicely. If I need to replace these vehicles in the future I will have to go back to toyota and will probally end up doing a 80 series or two.For now the jeeps are the plan and the builds will start soon so look for a new thread cataloging their progress over the next few years.

Thanks again to everyone!

[Alex]

Actually I am careful to not abuse my Cherokee. What you are seeing is 6 years cumulative effect of hard off road use. Now my buddy John is another story- this is 2 years of use, he trailers his Jeep everywhere:
http://www.fototime.com/6D3688FC311D185/orig.jpg

[Offroader5]

Any rig's frame or body will see those problems with "abuse". I have been doing the more technical trails with my XJ now for more than 3 years and still have not had any major damage. I have a couple small rock kisses in the body from crawlin, but that's about it. I however, am a very technical driver. I take it slow and if the line I'm on isn't working, I try another rather than push my rig and force breakage or damage. It is after all called rock crawling.

I run a large heavy winch bumper with winch on the front, and on it's install, the frame at the steering box was also plated both sides and I ran sleeves through at the bolts. More than likely when the frame gives out at the steering box, it's not due to the twisting force of the unibody, it's due to the frame's overall weakness not being able to handle turning the added torque and weight of the larger tires especially with the added angle of the drag link with the lifts. Also not to mention the added force needed to turn the larger tires when they want to stay stuck in the rocks or want to go the other way.

My 2 pennies....

[Alex]

Any rig's frame or body will see those problems with "abuse". I have been doing the more technical trails with my XJ now for more than 3 years and still have not had any major damage.
It took about 3 years for my Cherokee to start cracking... ;)

BTW, I really like your rocker protection!

[detailbarn]

alex yeah I'd say your friends jeep i much worse! I guess what each of us think is abuse or just hard use is relative to the area we live and type if wheeling we enjoy.


Offroader5 I agree with pretty much any rig is that see such hard stuff can and probally will see frame damage. I too am a very technical driver and living on the east coast the trucks will mostly see fire roads and well traveled trails with alot of dirt and mud with very little rocks. I'll also only be running 32's on the street and 33's off road on the MJ , the XJ will have 31's all the time. More stain then stock but much less then say 35's.


Thanks again for all the input!

[Offroader5]

It took about 3 years for my Cherokee to start cracking... ;)

BTW, I really like your rocker protection!

Thanks....have you seen my Rear Quarter Protection (http://smg.photobucket.com/albums/v126/offroader5/Body%20And%20Drivetrain%20Armor/?)? :) :)

[Alex]

Wow, beefy! Did you fab up the 1/4 sliders yourself, John? Are you going to put tubes at the roofline too? That area of a Cherokee gets a substantial amount of abuse due to the soft front coil/stiff rear leaf suspension design.

[Offroader5]

Wow, beefy! Did you fab up the 1/4 sliders yourself, John? Are you going to put tubes at the roofline too? That area of a Cherokee gets a substantial amount of abuse due to the soft front coil/stiff rear leaf suspension design.

Yeah, I did the slider rails....took some time on those notches for sure :mad:

Yeah, I am going to have some protection for the roof. Those quarter sliders are the mid point horizontal for future C & D pillar uprights that will go up to roof sliders that run full length. The truck will end up with a full exo and I am trying to design it so that I can build areas at at time, but not look stupid as I do :)

[Alex]

Sounds good... where do you live? I'm bringing my Jeep over so you can weld in some T&T frame stiffeners and fix this: :D

http://www.fototime.com/E5E3E12340EC91A/orig.jpg

[Offroader5]

Sounds good... where do you live? I'm bringing my Jeep over so you can weld in some T&T frame stiffeners and fix this: :D

http://www.fototime.com/E5E3E12340EC91A/orig.jpg

Now see...shame shame :violent-smiley-031: That should have been one of the first things you did to that axle when you lifted it....that needs a plate on the front side as a gusset.

I am in Apache Junction, AZ...........bring it over...we'll get 'er fixed up :REExeSquatsHL1:

[Alex]

Is there anything else I should plate or reinforce? I was hoping I had already exposed all of the weaknesses found in the Cherokee platform.

http://www.fototime.com/5966C7BD3E457F9/orig.jpg

http://www.fototime.com/9832B4AC9393B0B/standard.jpg

http://www.fototime.com/EC777B612605317/standard.jpg

[Offroader5]

Is there anything else I should plate or reinforce? I was hoping I had already exposed all of the weaknesses found in the Cherokee platform.

http://www.fototime.com/5966C7BD3E457F9/orig.jpg

http://www.fototime.com/9832B4AC9393B0B/standard.jpg

http://www.fototime.com/EC777B612605317/standard.jpg

How much lift are you running...5", 6"? One thing (which seems evident that you already know), that stock Y steering is weak. An easy fab up for steering is to use some .250 wall 1.5" DOM and build a wheel to wheel tie rod using some 3/4 ton GM TRE's.

Then using the same material you could either fab the drag link to attach to the tie rod somewhere toward the passenger end...or do like I did and use a Blazer passenger TRE that has provisions for a steering stabilizer mount that can be reamed out for a standard TRE instead.

If your not running too high a lift, then you could be just fine with the stock Y setup, as long as it's upgraded in the strength area. I have never liked the Y design though cause as your wheel travels up and down, the toe of the wheel also changes...which is why when you lift an XJ, because of this design, the tires toe in at the front due to the increased angle of the drag link.

Here's what mine looks like:
http://smg.photobucket.com/albums/v126/offroader5/Suspension%20And%20Steering/th_image019x.jpg (http://img.photobucket.com/albums/v126/offroader5/Suspension%20And%20Steering/image019x.jpg) http://smg.photobucket.com/albums/v126/offroader5/Suspension%20And%20Steering/th_image020x.jpg (http://img.photobucket.com/albums/v126/offroader5/Suspension%20And%20Steering/image020x.jpg)

Definitely (if you already haven't), plate up both sides of the frame at the steering box, and use sleeves through the frame for the 3 bolts so you can really crank them down without squishing the frame.

Mine's part of the bumper brackets:
http://smg.photobucket.com/albums/v126/offroader5/Just%20Some%20Pics%202/th_frontbumperwinch2.jpg (http://img.photobucket.com/albums/v126/offroader5/Just%20Some%20Pics%202/frontbumperwinch2.jpg)

BTW....that broken main leaf is the reason why you should carry at least 2 or 3 pairs of Vise-Grips in with your trail gear. I'd prefer the C-clamp type with the little flat swivel feet on the jaws. They work great for clamping the leaf back against the rest of the pack, to at least limp it off the trail.

Another area would be the upper frame mount for the track bar. It looks like your still running the stock mount, which is ok, but you might want to think about getting an HD mount. But don't stop there. You should also plate the outer face of the frame at this mount (you can incorporate this with the outer plate that you put on for the steering box). Then after you bolt the HD mount in place....WELD it on. IMO, anything that is an OEM "bolted on" condition that you don't think you'll ever have to constantly remove...should also be welded on. Not only is it stronger now that it's welded, but if the welds do fail, you still have all the bolts through it to keep you going.

Ok, I have rambled on enough...there are alot more tech pics HERE (http://smg.photobucket.com/albums/v126/offroader5/) that can show you even more shots of the steering and other things that I could be forgeting. :)

[Alex]

Great photos, John! I love the custom Clodbuster. Here's a pic of my buddy's Wagoneer you might like:
http://www.fototime.com/5A6B7AEAA43A75F/orig.jpg

I had both frame rails plated and sleeved back when I had the issues with the steering box.

The steering is ok, I'm at 5 inches of lift and recently put on the Currie steering. It is at the body shop now getting the axle bracket and frame stiffeners installed. I'll see how tight it feels and report back.

[IXNAYXJ]

Thanks....have you seen my Rear Quarter Protection (http://smg.photobucket.com/albums/v126/offroader5/Body%20And%20Drivetrain%20Armor/?)? :) :)I've got the THOR guards as well, and they've saved me many times. They're back in production too, so if anyone is interested in getting a set just e-mail me (madair@jpfreek.com).

http://www.pnwzj.com/Moab2007/moab%20%20brian/moab%20%20brian%20092.jpg

-----Matt-----

[Offroader5]

Great photos, John! I love the custom Clodbuster. Here's a pic of my buddy's Wagoneer you might like:
http://www.fototime.com/5A6B7AEAA43A75F/orig.jpg

I had both frame rails plated and sleeved back when I had the issues with the steering box.

The steering is ok, I'm at 5 inches of lift and recently put on the Currie steering. It is at the body shop now getting the axle bracket and frame stiffeners installed. I'll see how tight it feels and report back.

That's a pretty slick shot. Makes ya think for a second where the guy was standing when he snapped it. :)

[PolishX]

here in alaska XJ's are king it seems like .,Sven has seen the Alaska XJ's up close ...although not as cool as my old full width 383 powered FJ60 .. BUT I wheel one now and with steering box brace and some tweeks 35's with a locker in each end is no problems for 200K plus