XJ/MJ Concerns

detailbarn

Adventurer
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.
 
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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.....
 
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.
 
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.
 
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 :-))
IMG_5499.jpg
 
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.
 
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...
 
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:
 
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.
 
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 said:
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.
 
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.
 
Fat_Man said:
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.
 

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