Jeep unibody strength

[Viggen]

I had a 90 Cherokee (32's, 4.5" lift, 4.7L) and it was pretty good, if not a little small, for me and what I was using it for. While Im interested in a SWB for trips, a friend of mine really wants a 4.0 ZJ to build up to off road and serve as a trip taker. He is a little concerned about the unibody strength though when it comes to winching and lifting. I never had a winch on my XJ but had read about and seen pictures of bumpers ripping off of the fronts under stress and hes concerned about the strength of the ZJ with its 16 gauge frame. Anyone experience any frame troubles due to weight, winching etc...? Im telling him not to worry about it but hes curious.

 

[alosix]

I wouldn't be too worried about it.

On XJs the trick is actually getting the winch bumper on there 'correctly'. If you shortcut the process and don't use the brackets that tie the bumper in pretty far back on the 'frame' its not held on by much and can come off.I would imagine that a ZJ is pretty similar in that regard.

FWIW. An XJ was the winch point/winch truck for the 'backdoor' obstactle during the king of hammers race a few weeks ago for the 2 days of last chance qualifiers. Translation : Nearly 200 buggies used it as a winch anchor while beating their way up the obstacle.

I would be a little worried if you were constantly running hard trails with a ZJ without adding some frame stiffners. After a few years you'll just overwork the poor thing. Doors might stop closing right, windows in the back popping out.. etc.

 

[adrenaline503]

I cracked my "frame" on my old XJ right above the rear wheels. I have no idea how, never did anything hardcore. I would recommend reinforcing that area with a few plates.

 

[Root Moose]

I'm not sure about ZJs but you can buy enough stiffeners from the aftermarket to plate an XJ from front to back.

Supposedly the WJ unibody is a lot stiffer. I don't believe it. We were led to believe that 97+ XJs were stiffer than the originals but it still is not that stiff.

I say plate where appropriate. Unibodies are good, fatigue is a **********; just takes work to solve.

 

[zjsheller]

My ZJ has been contorted in about every position imaginable. I've just about lifted myself vertically with the front winch. I've never had a problem with frame cracking. Just about the only problem I've found is if I have to open the rear hatch when very off camber, it will not close til I get myself on flat ground. I think the ZJ is a very underrated off-road/expedition rig.

 

[purdueXJ]

I'm not sure about ZJs but you can buy enough stiffeners from the aftermarket to plate an XJ from front to back.

Supposedly the WJ unibody is a lot stiffer. I don't believe it. We were led to believe that 97+ XJs were stiffer than the originals but it still is not that stiff.

I say plate where appropriate. Unibodies are good, fatigue is a **********; just takes work to solve.

I don't know how much truth there is to this, but supposedly Chrysler hired Porsche to make the WJ's unibody stiffer. This is according to wiki.

 

[BIGdaddy]

bumpers ripping out are due to poor aftermarket bumper design.

look at these companies for quality front frame stiffeners/winch bumpers

-JCR offroad
-Detours offroad
-Logans metal offroad products
-AJ's fabrication

Those guys know their stuff and make products that have been used, abused, tested and approved.

 

[jh504]

The last thing I would be worried about building a ZJ is the unibody. Finding a reliable ZJ is like finding an unreliable XJ, few and far between.
I have seen unibodys wheeled VERY hard though for years and have yet to see any major problems. My XJs did get annoying sometimes with the rattling though. It seemed like the unibody would let the Jeep body flex which would make little parts in the Jeep rattle over time.

 

[BIGdaddy]

The last thing I would be worried about building a ZJ is the unibody. Finding a reliable ZJ is like finding an unreliable XJ, few and far between.
I have seen unibodys wheeled VERY hard though for years and have yet to see any major problems. My XJs did get annoying sometimes with the rattling though. It seemed like the unibody would let the Jeep body flex which would make little parts in the Jeep rattle over time.

I'm confused by your post a bit.

Are you saying that he shouldn't worry about unibody strength, rather he should be focused on the lack of reliable drivetrain, in your opinion?

If so, I agree. haven't heard much good things about ZJ's unless they have the same 4.0L/AW4 drivetrain that the XJ has.

Oh, and by the way, I think I've heard of ZJ's with a rear d44. Just fyi, this is not a standard d44. its like a "d44a" or something like that. Aluminum center section, no aftermarket, no bueno.

 

[jh504]

I'm confused by your post a bit.

Are you saying that he shouldn't worry about unibody, strength, rather he should be focused on the lack of reliable drivetrain, in your opinion?

If so, I agree. haven't heard much good things about ZJ's unless they have the same 4.0L/AW4 drivetrain that the XJ has.

Oh, and by the way, I think I've heard of ZJ's with a rear d44. Just fyi, this is not a standard d44. its like a "d44a" or something like that. Aluminum center section, no aftermarket, no bueno.

Sorry for the confusion, I ramble sometimes. Yes that is what I was referring to. I have owned both ZJs and XJs and used both offroad and I have had nothing but problems with the ZJ. Even with the 4.0/ AW4 I had computer/ electronics related problems. Never had an issue with my high mileage XJs. I am not slamming ZJs though, they are very capable rigs, just saying that there are some other problems I would worry about more than a unibody.

 

[BIGdaddy]

Sorry for the confusion, I ramble sometimes. Yes that is what I was referring to. I have owned both ZJs and XJs and used both offroad and I have had nothing but problems with the ZJ. Even with the 4.0/ AW4 I had computer/ electronics related problems. Never had an issue with my high mileage XJs. I am not slamming ZJs though, they are very capable rigs, just saying that there are some other problems I would worry about more than a unibody.

10-4...no worries. I HAVE had only one cuppa coffee this morning, too, and that's not helping things either..

haha!

Thanks for posting your experiences, good info for the OP.

-B

 

[jh504]

10-4...no worries. I HAVE had only one cuppa coffee this morning, too, and that's not helping things either..

haha!

Thanks for posting your experiences, good info for the OP.

-B

:coffeedrink: ........ :Wow1:

 

[CRD Liberty Joe]

Unibodys wear out! I wheeled an XJ for some time and no question the body wears out! Of the unibody vehicles the KJ is the strongest Jeep ever made.

 

[Desert Dan]

If you are worried about a unibody get a vehicle with a real frame.

On rough trails you can feel the body flexing so much your hand can get pinched between the door and the roof rail. This happend to me in a friends Cherokee on the John Bull in So. CA.

I didn't think the uni-body would be flexing that much

 

[Xjaddiction]

If you are worried about a unibody get a vehicle with a real frame.

On rough trails you can feel the body flexing so much your hand can get pinched between the door and the roof rail. This happend to me in a friends Cherokee on the John Bull in So. CA.

I didn't think the uni-body would be flexing that much

I can feel the same thing with my Ford F-350... All bodies flex... If they didn't they would crack...