It's my first time building an XJ. I want to build a Crawler/Overlander for a trip or two this summer. I just bought a 4.0 automatic XJ a couple of days ago, and I'm picking up tons tomorrow. It's in good shape overall, very little rust, none of it structural. Everything that is worn or damaged, I plan on replacing anyway. So I feel like it's a good starting point.

First question. How much tire can the 4.0 turn at highway speed with appropriate gearing? For crawling I want the biggest tire that can reasonably be used, but for overlanding I need to be able to drive it on the highway too.

Second Question. What frame stiffeners are strongest? I see that most of them are very similar, but I don't really know if one has a better reputation than others.

Finally, I have a very worn suspension. It's sagging really bad in the back, and the front floats around a lot. I'm thinking I'll probably go 3 or 4 link in the front, and I haven't decided in the back yet. I may go 4-link or I may just put new longer leafs on it.

Eventually, I want to do an LS swap, but I'm in the middle of moving and building a house this spring, so I don't really have time for that part right now. Any knowledge you can offer is greatly appreciated.

How much tire you can turn depends on gearing. 4.56 will do for 35 or 37s And I assume you can fabricate? Tons don't just bolt in

seems like a steep bill for just a trip or two and this summer is not far away

Fabrication is not a problem, I'm perfectly comfortable with that aspect. I'll need to do some research and figure out the proper geometry for everything, but as far as the actual fabrication goes, it's just another day at the office. I've got 35's on my YJ with 4.88 gears, It's a 95' 4.0 with a newer NV3550 trans. It's wound a little tighter than I want at highway speeds. I know 37's would help achieve a higher speed at the same RPM but, I worry it may be too sluggish getting to that speed. Since road trips are in my future, I don't want to risk overheating my engine or transmission by overloading or over revving it.
It's not for just those trips, but those are coming up this summer. I plan on keeping it around for a while. As I said, I would like to do an LS swap, probably just a 5.3/4l60e combo, but I don't have time with building a house. Lucky for me. I got a job where I only work Friday Saturday and Sunday. So I have four days in a row off every week, and I am currently living in a very nice apartment in a big pole barn with all the fabrication tools I need, a two post lift at my disposal, and a nice little bar. Pretty much all dedicated to off road toys, and generally questionable shenanigans.
I'm hoping this will be enough shop time to get me ready. I've got a substantial amount to spend on it, but I need to buy another daily driver too, and I'm not one to spend money on pointless stuff.

This is kinda my intent for my rig as well. Its a hard mark to hit because those two things require compromises on both ends.

I personally feel that tons are overkill for anything other than a trailer queen. You will be able to work with them, but know that you'll need to essentially build the rig around them. I'd recommend doing everything you can to lighten them up and make them as small as possible. I looked into this a good bit before deciding to go for a 44/9 setup. I was intending to do a 60 front narrowed to ~65" WMS with a shaved bottom and a 5x5.5 conversion with 3/4 ton brakes. Was also planning to pair that with a built up 9" rear end. I ultimately decided the front was more work than it was worth for my needs and a 44 will suffice.

To build a rig that will last in case you're describing will require a thorough and well thought out build. I recommend starting with frame stiffeners all the way down, tube rockers, and a cage. There will be way more unsprung weight than the body was designed to handle. You need to increase the rigidity of your chassis. Pay special attention to reinforce the area around the steering box, as its common to overstress the unibody rail there and crack it. Plan on bracing the box and tying it, as well as the track bar mount, into the opposite side frame rail.


This is a subjective question. It can turn as much as you want. How willing are you to wind your motor out? Wanna run 54" tires with 7.17 gears? Have at it.

Use this calculator: http://www.grimmjeeper.com/gears.html

And charts like this one: https://www.google.com/search?q=jeep...r_eUWPCETQ6HJM

to get an idea of where you want to be. Knowing you're planning an LS, I'd image you can get away with being slightly under geared. That will also be good for the highway. Bad for your transmission though. Definitely add a transmission cooler. I image you'll want something in the 37's and 4.88's up to 40's and 5.38's range. I'm doing 35's and 4.88's.

I'd argue its more in than installation than the actual product (to an extent). They are similar. I have Ruffstuff midsections, which are .188" thick, and Dirtbound front and rear, which are .135" thick. I've found it to be a good setup. I'm not very familiar with the current options for stiffeners, but if I were to do it again I'd pay attention to kits which wrap around the unibody rail more than others. Again, you need to build the strength into your chassis.

Take every suspension component you currently have and throw them into the corner. Plan for a total rebuild. You'll need a custom steering setup, and will want to go long arms up front. You'll probably want hydro-assist to help turn those big tires. Are you gonna do long travel shocks, or work with the OEM mounts? If long travel, you'll need shock towers fab'd in. If you're going coils in the rear, you'll need some well thought out fab work on that as well. You've got some decisions to make and planning to do.

In my opinion, your goals are far too ambitious to have this ready for this summer. Could you slap those 1 tons in and send it? Sure. But it would not last long with that setup. It would be awful to drive on the road, and not perform well on the trail. I would not call it an overlander/crawler build.

All that work I just mentioned is completely to support one tons and make this a well performing crawler. Barely touched on the overland setup. That's another can of worms. How deep do you want to go?

It is going to be a compromise on both ends for sure, and it's going to be heavy. Frame stiffeners are going to be the one of the first things I do. I'll look at reinforcements for the steering box and track bar as well.




I was talking with a someone last night and came to the same conclusion. Adding a transmission cooler is in order.

I'm thinking I might go with 37's and 5.13s and possibly an atlas. I have to see what it's going to cost me to convert it over to my LS Swap later. I don't want to put a ton of money in it to mount it to an AW4, just to later put a ton more in to convert it to a chevy transmission.



Lol, The only suspension component that isn't headed to the scrap yard is the leaf springs, and those are headed to the forge where my dad will want to make knives out of them, or at least stock pile them saying he wants to make knives some day.

Up front is definitely going long arms and hydro steering. The only question is hydro assist or full hydro. Full hydro and 4-link should relieve stress on the frame, if I'm understanding it Correctly, but so should hydro assist to an extent. The shock towers are an area I still need to research, but I imagine they will need extended and tied together, no matter what. It's just a matter of how much. It's getting to the point where buying a tubing bender is starting to look more reasonable than buying pre made parts, and I've wanted one for a couple of years, so that may happen.




​​​​​I realize it's a very ambitious plan, but I've got a couple of things going for me. First, I've got a pretty good budget to start with. Second, I get 4 days in a row off of work every week. Third, I live in an apartment in a pole barn with a large shop with a lift and lots of fab tools right out my front door. I also have a lot of help available. So I'm hoping it's doable.

As far as overlanding goes, I'm really just concerned with making it drivable enough to get to and from the location reliably. I'm not too concerned with making it an integral part of the rig. I'm not planning roof top tents or pull out kitchens or anything extreme like that. It just has to get me, my wife, and a couple of totes, there and back, hopefully without incident.

Thanks for the Input.

Here is something to consider. The LS engines are designed to cruise at a low rpm so they can have some resemblance of milage. And since you are considering an Atlas, You can choose your crawl ratios since they build them to your specs. I am building mine right now and have an Atlas 4 speed. It has 2.7, 3.8 and 10.38 ratios. The point here is that these ratios allow you to have highway gears and still crawl as slow as you want. It is a departure from putting really slow gears into the diffs. So you could leave stock gears in the diffs and just shift the tcase for trails. The 4 speed allows you to do it all without compromise and is cheaper in the long run, or can be, than redoing gears in both diffs depending on whether you set up your own gears or not

I just picked up my new axles, I went with a D44 high pinion, and a D60.
The D60 has a lunchbox and disk brake conversion, the D44 has high steer knuckles, and a Lincoln locker. It came with a new carrier and an install kit though. They are setup with 5.13 gears.

​​​​​​Hopefully this setup with 37's will make for reasonable street manners.

That is a start. But do get rid of that welded carrier. Otherwise the only direction it will want to go is straight

I'm planning on ARBs, but for now I just want to get it under the Jeep. In the short term I'll just unlock the hubs when I don't need them.

Now I'm stuck trying to decide between 3-link or 4-link in the front, and shock towers or hoops. In both cased I'm not sure what is strongest or works best with the unibody.

I can't nail down exactly what year my D44 is. The guy told me he thought it was late 70's probably 78' or 79'. But I'm seeing things that make me think bit might be a little bit older. The BOM and date numbers on the tube are completely missing.

High pinion D44
open knuckle
Manual locking hubs8 lugsDisc brakesDual piston calipersLeaf spring perches

I've considered that, but at this point the concern is overheating the current transmission. I simply don't have time to do the LS swap before my trips this summer. With the current backorders, I'll be lucky to have the suspension done. Luckily the axles I picked up already have 5 13 gears, so the transmission shouldn't be too overloaded.

So you fabricate offroad suspension for a living or as a side hobby maybe you burn for Barnes or ruff stuff. Or maybe trailers.

another day in the Office, comments like that push my mind to assume oppisite of you. Though I have met a few soft handed office types that have some badassery going in theyre garage but they are very rare.

Just my thoughts