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Starting my XJ overland build, need advice


NAXJA Forum User
After wanting an XJ for years, I ended up buying one for my son’s first car. Having helped him fix his up over the past year, my desire to finally build MY perfect XJ overlander finally got the better of me. I bit the bullet and bought a 1997 4 door XJ Sport. I’m in love, but I need help! My goals for this vehicle are long distance trips across country and potentially over some rugged terrain. I don’t want to build a rock crawler, but I do want to build something that’s moderately capable off-road. Think more traveling and back-roading than off-roading. I’d like to drive from Louisiana to Alaska and back one day, so I figure I need to balance fuel consumption, storage capacity, and easy/cheap/available replacement parts with off-road performance. I’m looking for some Jeepers with overloading experience to guide me.

Here’s what I’ve got to start with:

  • 4.0L engine, about 140k miles
  • 5-speed manual (I believe its the AX15 but have not visually confirmed)
  • Command-Trac transfer case (NP231)
  • Dana 30 front/8.25 rear axles, 3.07 gearing
  • Trac-Lok LSD in the 8.25
  • Factory skid plates front and rear
  • 4x P235/75/R15 ATs
As far as I can tell, this thing was born and raised near Dallas, TX, and there’s barely a spec of rust anywhere on it. It wasn’t running when I bought it, but I quickly traced that down to the starter, so that’s new too. Runs like a top now. Also love that it has no power options. Manual seats, door locks, windows, transmission, everything. Electrical stuff breaks too much in these things.

In addition to factory/stock equipment, the previous owner made some mods:

  • Full width Hooke Road steel front bumper (not tied into the unibody yet though)
  • 9500# Rough Country winch with synthetic cable
  • Aftermarket MB wheels (need some help identifying these as I’d like to get a matching spare if I end up keeping them)
  • Curt trailer hitch
  • LED light bar
  • LED head lights
  • LED tail lights
  • LED fog lights
  • Simple bluetooth aftermarket single DIN stereo
It also came with a 64” roof rack, but I decided that for the time being my son could make better use of that than I could. Not entirely sure what I want to do up there yet. Have some pics as purchased:



So obviously I have lots of questions:

  • How much do I really need to worry about frame stiffeners? If I want this thing to last long and go far, but if I’m not really going to be wheeling it super hard, should I worry about them?
  • What are some of the first mods that you guys would recommend to make long distance trips more convenient/comfortable? I’m not planning on going alone, and I want my passengers to be as happy as I am.
  • I’ve seen that I shouldn’t choose a suspension until I’m pretty sure I know what the fully loaded vehicle’s weight should be. But, waiting to do that last could make it harder, and I don’t want to afraid to use this thing until its done. I guess this question is: in what order would you guys go about building an overlander from a more or less stock XJ?
  • Wheels and tires for overloading: what makes sense for my use case? I have read that 235s are about as big as I can go on stock suspension, and I don’t know what suspension I’m aiming for yet. Also I don’t know how one chooses wheel backspacing/offset. I know what that is, but given my use case, what should I choose and why?
  • The gearing in my XJ is some of the lowest you can get. Even with P235s, I’m probably pushing it to do much. To get a good mix of on and off road performance, where should I be aiming? If I up my gearing, does that mean my LSD will have to be replaced (and if so, is that a good or bad thing)?
I’m going to have a lot more questions over time. I will try to come back and edit this post with the answers I go with so others can benefit.

Thanks to all that post in these forums. We new guys are standing on the shoulders of giants!
If I were still in SoCal we would need to get together so you could see my '96. I have built it for the purpose you are seeking, and it started out very much like yours. 4.0L. AX-15 and 3.07s. My typical trip involves 1,000 miles of freeway, several days off-road, and then 1,000 miles of freeway back home. Reliability is crucial.

For the sake of reliability, make sure you go through and change all the fluids--engine oil, transmission (DO NOT USE ANYTHING LABELLED GL-5. Redline MT-90 is what I am running in my AX-15.), both differentials and the brake fluid. Fix any oil leaks you have. You haven't said how many miles are on this vehicle, but the odds are good you need to deal with the oil filter adapter and maybe the crank seals at both ends of the motor. Take out both driveshafts and rotate the joints in your hands, feeling for any rough spots. Pay close attention to the centering ball for the T-case. If that centering ball goes it can take your T-case with it. Check your front axle U-joints carefully. Figure out the condition of all your chassis joints and replace any questionable ones.

If your headlights are not yet on relays consider making that upgrade. Long drives with headlights on can add up on wiring that is marginal at best. Chysler was by no means generous in their wire sizing, and the years have not improved the resistance. I like LEDs for brake and turn signals--they don't get broken filaments when you shake them up on washboards. LED headlights might be nice too, but I have yet to spring for them. I am waiting to hear that Daniel Stearn is impressed by them (He has the best advice I know of on the lighting front).

Figure out how you intend to stow gear to keep it from shifting around while you are off-road. Somehow you need to tie things down in the back. But don't drill any holes into your fuel tank in the process. Speaking of fuel tanks--you should look into the Genright tanks. Not an option for my '96, but they should be an option for your '97. I know of no better way to carry extra fuel, but they are spendy.

I recommend frame stiffeners. Front stiffeners were the first substantial project I undertook on mine. I have also done the middles. I have the rear stiffeners but haven't gotten them done yet. If you are going to add weight and tackle rough terrain you really do need to do something to strengthen the chassis. If I had unlimited resources I would have a hybrid cage in addition to the stiffeners.

You will want to re-gear. What you re-gear to depends on what tire size you intend to run. I am running 30" tires at the moment, with a plan to go to WJ brakes that will take me to 30.5" tires (not much change). I re-geared to 4.10s and am quite happy with the combination. It is fine for off-road and is good for about 70 or 75 mph on the highway.

30" tires have worked well for me for overlanding. I am not trying to rock crawl. I am mostly on old mining roads. But sliders are a priority. I built my own (after plating the middle of the frame). I do not yet have skid plates, but those are on the objectives list.

My lift is probably somewhere between 2 and 3 inches. The front is a combination of parts of questionable provenance. The rear is OME (Old Man Emu) leafs and stock style rubber bushings.

I have an OX-locker in the rear and love it. I intend to install one up front too.

As for comfort, well, an XJ doesn't offer much. I keep my heat and AC functional. Only thing I can think of to change would be seats, but I don't have a problem with the factory seats. I have thought about getting PRP seats for the front. What most appeals to me there is the option of a hydration system built in. (There are no good cup-holder options.) One thing I have done that makes things more comfortable is to add a Lido mount for my GPS. I have been pleased with how well that has worked for me.

I should probably also note that my XJ is not just an overlander. It is also my daily driver and grocery getter. It is the vehicle I most prefer to drive. I like the fact that it is easy to get in and out of tight areas.

Best of luck on the build
To me 31s are a small tire and the smallest i would ever buy.
I'd buy them a make them fit. A trim here a sledge hammer tap there will help them fit a stock xj.

With 307 gears i wouldn't go bigger than 31s.
To me that pulls the lift kit off the table for now.
Some 31" traction tires, on stock or 15x8 16x8 wheels most are 3.5-4" of back spacing. I wouldn't be picky but if had a choice I'd choose 4" to keep tire more inside fender.

Get bumper mounted securely
Recovery and safety gear,
Straps, chains, snatch block, gloves, shovel tools, first aid kid emergency gear, food blankets water lights .
I've found packing stuff even just for a couple days i have to be creative. Also find i never have enough stuff. How do pack all this shit plus a full set of tools/parts in a little jeep and a spare tire.

See efforts are waisted on lift and all the negatives that come with a lift.

Winch is far more valuable than lift and big tires.

Get some practice running the winch doing test run pulling the xj up a long driveway or out in the hills.

I really think for your use its already nearly ready to go. It just needs set up and tuned

Load it down like your leaving for a week and see how much help the rear pack needs to support all your stuff. Adaleaf helper spring or combination with heavy duty new leaf pack

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I had an xj on 3 inches of lift, long armed, and 31s.... aw4 so that was different, but I loved that combo... roughly 11 inches of travel up front and 7ish in the rear. it did very well on the trail and awesome on the street. I miss that setup...
It easily ran 80.... also got 18 to 20 mpg on mixed driving.

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Stiffners aren't needed but a solid investment if you plan to keep the rig. As mentioned reliability is key. First mod would be making sure all basic service items are taken care of. Look at some easy upgrades, bigger alternator, solid tie rod, better battery cables, etc. A stock XJ is very capable. As for a lift you could either do a upcountry lift, which will get up about 1" from the coils and a shackle relocation for the rear to even it out. WJ lower control arms and some other odd and ends. Or look at old man emu or IRO for a basic lift. Don't need anything crazy but if you're going to lift it I would at least consider short arms. Gears I'd look at 3.73 or 4.10 on 30ish tires. Since you have a manual you can get away with not as deep of gears. For comfort, you could look at swapping in WJ seats. If you're really tall that may not be an option but they are super comfy. You could also consider stripping the interior to add sound deadener. XJs can get loud on long road trips.
I built and am in the process of upgrading that build on a 2000 XJ Fed auto. I wanted a DD with some Off Road capabilities and mileage.. It was suppose be a "budget' build. Didn't happen due to various reasons. Yours being a manual trans changes the gearing need. Actually good news for you.
My build is a 2 inch lift on 31's with 3.73 gearing. I do think if you contend with mountains, then 4.10s would be better. I do have an IRO rear bumper, Bad Dad Fab front hidden winch bumper, WJ big brakes, GM 1-ton cross over steering, Ford 8.8 rear end with LS, Cibie headlights and the wiring upgrade. Daniel Stern did advise me that the Trucklite LED and the other high end one are good. But might have issues if in cold weather, and icing up. I also did some exhaust mods. 2.5 cat back and a header. Mine came with the 99+ intake. I did bore the TB to 60mm. I notice a bit better shifting on the inclines in WV. Possibly a bit more MPG. I get 18.3 at time on the highway. I expected more. I also run KYB Monomax from and some cheap white rear shocks. It does good, but a bit stiff on the road.
I did add frame stiffeners. It was due to my rear frame rails being rusted out on the bottom. So, I bought those from Hooligan. Then I was buying stuff from IRO, so center section from them. Then of Ruff Stuff so a front from them. My next build is IRO rear, Hooligan Front and center. Mine handles well on curves. I also did M&T inner frame stiffeners.
Some of my future plans are a ZJ gas tank. Check threads on this board, should give 26 gallons. Upgrade the fuel pump. Probably not necessary. Change the head to a 99, and Chevy valves. Viper coil, not applicable to yours. Also, some improvement to the air intake. Right now I am messing with a WJ setup. Hood vents. Also, plan to switch out the 231 to a 241 transfer case.
So for yours, I'd probably look for a 2 inch to 3 inch lift. IRO or OME are good choices. I'd look at DPG Off Road for OME. 31's. Shocks, I might try Bilstein 4600's or Doetch Tech if they have some for you height of lift. Since a manual and possibly 31's, I'd look at 3.55's. So, stock axles from an Auto XJ. WJ Big Brakes and cross over steering. Also, might look at a rebuilt gear box from Red Top or Blue Top. A steel gear box spacer.

Edit: I have Core upper and lower control arms on my 2000. I have JKS on my '98. I have Brown Dog motor mounts on the '98. I plan to put them on the 2000. Other motor mounts not mentioned below are Stinky Fab and Ironman 4X4.
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Great advice so far. Keep it coming! One thing nobody has addressed is the factory LSD in the rear. Worth keeping at all? Will I have to toss it if I regear anyway?

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Great advice so far. Keep it coming! One thing nobody has addressed is the factory LSD in the rear. Worth keeping at all? Will I have to toss it if I regear anyway?

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The both Ford 8.8's I have in XJs have the LS. It does OK wheeling. One of my Neighbors has an 8.8 in his ZJ. He bashes it. He said the LS did well for say 2-3 wheeling trips. Then he went with a lunch box locker, then a full locker. The other poster will probably have a better view of it. Still, if your going deep into rough or remote terrain, then I'd go with at least a lunch box locker.
I didnt picture this as a deep dark terrain build.
I picture it back east headed through a snow storm on improved roads where a locker wouldn't be needed or wanted.

I think id leave whatever is in it and run it till you get some time in it and your wants and needs evolve.

A year from now you might have a cummins towing the trail rig all around the country hitting the badass technical trails

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Great advice so far. Keep it coming! One thing nobody has addressed is the factory LSD in the rear. Worth keeping at all? Will I have to toss it if I regear anyway?

Sent from my SM-N960U using Tapatalk

Its marginal at best. I'd save for a selectable. For an overland rig an ARB in one end (front or back depending on what you like) is more than enough. Plus the air compressor can help you with other stuff.

I've only ever had 5speed XJ's. I ran 31's on 3.07's at one point and it was ok. Replacing them with 4.10's made that rig a lot of fun.

If you want to get a little more gear and save money, buy some axles from an automatic XJ and get the bump to 3.55's. Would still be nice on 31's. I ran 32's on that combo for a bit, was great around town and for mild wheeling. Now I've got it on 4.56's with 33's. Love the combo but not the best for economy.
Is LA , Los Angles or Louisiana? It might make tires etc. a bit different. I see CA as mountains, and Louisiana as mud or swamps. Maybe too much 'Swamp People'. If snow is an issue, then the 3 Peak tires might be a good choice.
Another part of my build is to use Thule rack. The stock roof rack on my 2000 is a 3/4 one. Also, I've had issues with the full one on my 98 collapsing when I've put dry wall on top. Also, possibly a bit of a MPG increase, to store the roof rack inside.
As for MPG and gearing, I want my highway RPMs to be 2,200 or so at 70 mph.

Edit: I used : http://www.grimmjeeper.com/gears.html to calculate RMPs for 3.55 and 4.10's at 70 mph. AX-15, NP231, and 31's tires.
3.55 - 2,128 RPM
4.10 - 2,457 RPM
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For a over-lander your going to want a selectable up front and a tru-trac in the rear(or a hd rebuild for the factory lsd), no auto-lockers! Add to that good front/rear bumpers with frame tie-ins for recovery, a spare tire carrier, and good rock rails.
The others have pretty much covered it, but I'll toss in a couple things too:

1. Quick disconnect links for the front swaybar - will make the ride better on "less civilized" terrain, and easier to deal with than unbolting the factory links (especially if they've never been disturbed).

2. In addition to getting that front bumper tied into the frame properly, make sure you've got a good rear recovery point - a class III (2 inch receiver) hitch, or a stout aftermarket rear bumper with receiver/shackle tabs. In both cases, proper tie-ins are needed here too. If you don't mind the notion of a little "massaging" to get them to fit, I highly recommend the "Circle S" brackets sold on eBay - full 2x6 tube-based insert that doubles as nut strips (see also gas tank skid mounting) and also provides good bracing to the 8 OEM rear bumper bolting points. These things are very stout, reasonably priced, and not hard to install.

3. Already mentioned above, but I'll second the suggestion for aftermarket lower control arms - the stock ones are thin and bend easy. Look for something with at least one end using rubber bushings (for ride quality) and adjustable (future upgradability)

4. Upgraded motor mounts, something with rubber bushings. Brown Dog is popular around here, but there's also the M.O.R.E. JM600s which I've run happily for over 10 years now. Might be a slight increase in vibes at idle, but OEM smooth otherwise and will definitely keep your fan and radiator apart off-road.

Finally, if your experience off-road is minimal, get out on some trail rides and start learning how your Jeep (and you!) behaves in various terrain. Also gives you a chance to see how the amount/layout of gear will affect behavior/performance too.
Man, all you guys are fantastic! I'm getting replies faster than I can respond. I want to address some of these things specifically and I will, but a quick message here to say thank you seems appropriate.

Also, is it not possible to edit a post on these forums? I was going to go back and edit the original post with decisions, info, maybe some more pics. Guess I can't do that?
No editing of previously posted messages on this forum.

Do you have a target budget range?

Since you are talking about 235 tires, it sounds like you intend to keep this a budget build and stay with the wheels you have. However, if you are open to new wheels and tires, here are my thoughts on that:

You'll most likely want to run an 8" wide rim either 15" or 16" diameter.

If you go with 15" diameter, you'll mostly be limited to SAE tire sizes, e.g., 30", 31", 32", 33" diameter. There's a ton of selection is the 31"x10.5"x15" size, but there is very little available in the 32". There's a ton of selection in 33"x12.5x15" size. 31" can be run with no fender mods (on a sufficiently lifted XJ). I think its case by case for 32", and 33" definitely needs fender mods if you plan to use the full travel. A 15" rim is the way to go for 31" or 33" tall tires.

If you go with 16", its metric tire sizes. A 265/75-16 is a very common size and is roughly equivalent to a 32"x10.5". If you want to go with a 32" tall tire, this size offers way more selection than a 32"x11.5" tire.

For an 8" wide rim, its easy to find a lot of rims with 3.75" backspace. This is quite a bit more offset than stock, and even a 10.5" tire sticks out past the stock fender quite a bit. For reference, the stock wheel offset applied to an 8" wide rim would be 5.75" backspace.
There have been suggestions by some forum members that a 3.75" backspace is hard on the steering knuckle ball joints. This low backspace also trashes the scrub angles which causes the front tires to skid on tight turns. My feeling is that a 4" backspace is the most I'd want to run, and 4.25" or 4.5" make more sense. Rim selection is limited in those offsets, but there are sufficient options both in steel and aluminum.
That's not the best advice. A 7" wheel is better for up a 10.50 tire and a 16" wheel would most likely be needed for a brake upgrade so keep that in mind.
That's not the best advice. A 7" wheel is better for up a 10.50 tire and a 16" wheel would most likely be needed for a brake upgrade so keep that in mind.

Aren't you running an 8" wide wheel with your 265/75-16s (which are 10.5" wide)?

16" wheels are just a means to an end which is to run a 32" tall tire. There is very limited selection of 32" tall tires in the SAE size range.

But my guess is that the OP will go with 31" tall tires if he increases tire size.
I'm not trying to make this a budget build, but I do want to make smart purchases in the right order. This is probably going to unfold over time, but better to do the planning up front. My main priority right now is to get everything mechanically sound and then start making short range trips to work out what gear I'll need. If I have wheels and tires that are good enough to do that in the short term, I won't look at changing those yet.

But yes, in order to keep my eventual lift to a minimum and keep as many of the stock suspension components as I can get away with, I probably won't ever go larger than a 31" tall tire. Probably 31x10.5x15 ATs. I would rather have steel wheels for repairability, but I'll get there eventually. I will consider R16s for brake mods though. Haven't thought about that yet, but I suppose that could happen down the road.

Curious why a 7" wheel versus 8" is better for a 10.5" wide tire? Is it pressure on the bead?

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Yes, pressure on the bead.

If you follow Matt's Off Road Recovery he has been down that road. He went to wide wheels and suddenly was breaking the beads left and right. He wound up going to beadlocks to solve the problem, but he recently commented that the rim width was the real issue.

Regarding the ability to edit posts, that is available to red letter members.
The latter XJs did have 16" rims as an option. I have them on my 2000. I do run 265-75-r16. Mine are E code (10 ply). I wanted c (6 ply), but the past year or so, you take what is available. I don't know what MPG penalty there is.
I do have Stinky Fab OTK trackbar on the 2000. Rusty's on the 98. The 2000 has the Stinky Fab Trackbar brace and the Bad Dad Fab bumper setup has a steering box brace. I have a Kevin's on the '98. I did have an Ironman steering box brace on the '98. (edit: Ironman more stought. Just trying stuff.)
I also have a 'mini' truss on the d30 on the 2000. 'Dirty 30' ( K-Suspension), and Stinky Fab spring bracket filler plates.
Since you want to take it in stages, I'd plan what height and tires. As before 2" to 3" is good for the road and 31's. Shocks, ???. I might try KYB silver or possibly the G3s. Doetch Tech if they have them for your lift. Possibly Bilstein 4600s. I'd start with a MORE or other steering box brace. Replace the stock aluminum steering box space with a steel one, IRO, Ironman, others out there. I might try Black Magic front pads. I have a set for the WJ Big Brakes, but have not installed them. People rave about them.
On the axles, I'd get a D30 from an Auto XJ with 3.55 high pinion. Then I'd look as to getting an 8.25 with 3.55 vs the cost of regearing, as to keep your LS. I think the cuttoff to regear is 3.73, the 4.01 and up need a different carrier.
I would see what front swaybar you have. The HD is 28mm or a bit bigger. Mine handles well with that and with poly bushings. I am replacing mine with an OME one for a WJ 28mm. I need to width to clear the frame stiffener and Bad Dab Fab bumper mount. My rear might need an upgrade on the swaybar. I plan some Bilstein shocks I have for the rear. Then see what it feels like.
As to trackbar braces, they are special or fit to the makers trackbar bracket, except maybe the Northridge one. I have Stinky Fab (installed), Rubicon Express (other brackets didn't fit, and the Stinky Fab was put in). And Ironman 4X4.

Edit: I'm going to add a test as to what gearing you might want. Note the previous RMPs at 70 MPH. At your present gearing and tires, I think that would be in 5th gear. That should be an Over Drive gear. I sometimes downshift to 3rd, with an auto trans and its about 2400-2600. I think 4th with your manual would do the same. Note noise level. Remember is you are going to drive highways for more than an hour, you will hear it and pay for it. Also, you could go with a NV321 with 4:1 ratio if you plan for rougher terrain. I don't think your intent is for that presently. So, I'd just keep the present transfer case.
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