XJ Overland build plan, need a sanity check.

[kayakbrian]

If I'm posting this in the wrong forum please let me know. Need some advice on a build I'm planning. Yes, I did use the search function, every day for the last week. I think I have a solid plan but looking for a sanity check from those who have actually done this:

I've got a 99XJ 2 door with 130K on it, a new engine, new radiator, and all the normal maintenance kept up on. * It's on 29" tires with a garbage Rusty 2" lift from the previous owner that rides like the wheels are bolted to the frame. *Gearing is stock, auto trans. *D35 rear axle. *

I've had it for a couple years now and the girlfriend and I use it for solo overlanding, *driving 1000-2000 miles on the freeway, then loading it to the max GWVR with gear and water for 7 days at a time in very remote places. *We don't wheel on purpose, just to get to get past obstacles. *It's surprisingly capable as it is, but I feel like a little more room under the pumpkin and a locker would make a big difference in both capability and safety for us. *The biggest issue is always sand, we've had some pretty sketch moments driving fast in 4 low where if I had lost momentum I'd probably still be there!

Up until now I just didn't see the benefit in dumping serious money into it, but we were 2 days away from wheels up on a major trip when the front diff exploded on the freeway (huge BANG, then couldn't move in any gear with traffic screaming around me) and it made me realize that we've been rolling the dice harder than I thought, and I no longer trust the rear D35 either, so I'm def gonna have both diffs rebuilt, but considering the cost of that and that labor is basically free for locking and adding stronger axle shafts at that point, I'll probably do that as well to get us more reliability and capability. * Of course at that point it seems dumb to go back to stock ratios and put all that work under a suspension that I hate. *So it seems like now is the time to regear, lift, and put on some bigger tires, all of which adds up to some pretty serious $$$.

I'm limited to 31's because in my case I have to put the spare in the back *(rear carriers steal too much payload and my roof rack normally has small boats on top). *I'm also VERY concerned about getting the gear ratio right for best MPG on the highway. *We drive 65 here, 55 in Mexico! * My locker choice really depends on what is going to work best on sand and ice. *Sand is more important than ice.

So here is the current plan:

4:10 regear
Stronger front axle shafts
stronger rear axle shafts or a 8.25 swap
3" OME lift, shocks and springs with an extra spring in the rear for the weight
new cheap 15" wheels and 3.5 backspacing
31" BFG KOG2's
Rear locker??? *Was gonna go with an OX but I'm open to a lunchbox if it's not gonna be sketchy on snow or ice? *Anyone with real experience with both?
LSD front? *waste of money, overkill?
Stronger Adjustable lower front control arms? *overkill or a good idea? *(already have a track bar)

Anything else I'm not thinking of here? *Anything I'm thinking wrong about? Hoping for feedback from people who have actually done something similar, not just repeating what other people say. *I appreciate the help. *It's a big investment and I don't want to screw it up.

 

[maxbraketorque]

- 4:10 regear will be good for offroad on 31" tires. On the road, the engine will be spinning at 2500 rpm at 72.5 mph.
- No need for stronger axle shafts unless using an actual locker. A limited slip will be fine on stock axles.
- If you aren't rock crawling, I suggest a torsen style limited slip diff (e.g. Eaton Trutrac) front and rear. These have great road manners, and will make great offroad traction until a wheel is lifted.
- 3.5" back space on the wheels is seriously kicked out. The most common offset for 15x8" wheels is 3.75" which is what I have on my XJ. My feeling is that a 4.5" back space is pretty good.
- 3" lift sounds good to me for 31" tires. I think my 4.5" lift is a bit overkill on my 31" tires.
- If at all possible, move to a long arm front suspension.
- Shocks make a big difference in ride quality.
- Beef up the frame around the steering gearbox. A steering gear box brace and a track bar bracket brace are both good things to have.

 

[Anak]

I think your plan sounds good. It is pretty comparable to mine, and I use mine in a very similar way (Drive 1,000 miles on the freeway (fully loaded), go wheeling for a week (Generally old desert mine roads) and then do 1,000 miles of freeway to get back home).

I have a '96, 4.0L, AX-15 with probably about 3" of lift, 30" tires (yep, spare inside the back) and 4.10 gearing. Works well for me.

I upgraded the rear to a Dana 44 with an OX Locker. I believe the key to a successful OX Locker is the routing and control of the cable (assuming you go with a cable operation--there are alternatives now). The cable needs all the same management as a parking brake cable. I think many installations end up being unreliable because folks aren't willing to invest the effort in cable management for long term reliability. Here is a link to my OX Locker install: https://www.naxja.org/forum/showthread.php?t=1143723

My front axle is currently open, but I have plans to upgrade it to an OX Locker as well. Both axles will have the largest available shafts once done.

My front suspension is a collection of parts, most not particularly great quality, but all stronger than stock. Most important is the double shear track bar mount, welded in.

My rear suspension is OME springs and Bilstein remote reservoir shocks.

You have not said anything about frame plating. At the very least you need to do some reinforcement for the steering box.

If you have not upgraded your motor mounts, that is something I would advise you consider. Putting the fan into the radiator is sub-optimal, especially on the trail.

Being that it is a Jeep there will always be something else it needs, but as long as it works, enjoy it.

 

[75SV1]

I didn't plan mine as an Overland. Yet, I am heading that way. Mine is a 2000 Fed XJ. I went with a Ford 8.8 in the rear. 3.73's and LS. Kept the Dana 30 up front. Crown Up Country rear springs and 2" IRO fronts. IRO rear bumper, Bad Dad Fab front bumper, that a hidden winch and includes steering box brace with sector shaft support. I used a D30 out on a ZJ for the 3.73 gears. Stinky Fab spring bracket fillers. Also, a Mini Truss from ??, its their Dirty 30 setup. Also, Stinky Fabs OTK parts and trackbar brace. Ironman and RE are others I have, but not installed. They will go one some other projects.
I have Rancho adjustable in the rear and KYB Mono Max in the front. Mono Maxs a bit stiff.
I also did a WJ Big Brake and GM 1-ton cross over steering. See Ruff Stuff. I also plated the frame inside and out. I used IRO center, Hooligan rear and Ruff Stuff front. I like Hooligan, especially for the center. I order his for the front and center on another build.
I am on 31's. Wild Country 10 ply (E). OK, and rides good. Probably way better out there. I did have another XJ on 4.10's and 31's. Did good on the highway.
The Ford 8.8 LS will hold up for limited wheeling. Also, I did a header, bored TB, 2.5 cat back. Helps a bit on mountain grades. I'd suggest 4.10 gearing if out west, maybe 4.30.
What I'd do different or plan to do: First I really like the 2" lift for what I do. I haven't tested this setup off road, though. I'd go 2.5 to 3 inch lift. Probably OME. The rear springs for OME are a dual rate. I have a 3.5 set. I might go with that and the 3.5 Metal Cloaks front I have. Possibly a long arm and an OX locker up front.
Presently, I am doing a mini stroker. Have the check the CC's in the cylinder head chamber. Waiting on roller rockers and a timing chain set from Russ Pottinger.

Edit: On Go_Jeeps website he made extensions to tilt the rear seat forward. Then he could get 32's in the spare holder. I don't think I had issues with 31's.

 

[Skruffy]

I used a lunchbox locker (power trax) in the front of my XJ for almost 10 years. I thought it was great. Pretty easy to instal and is only engaged when you are in four wheel drive and are applying throttle.
The other thing it does is slow down all your wheels to the speed of the one with the most grip, preventing breakage if you are being smart.

 

[Phil]

If you put an ARB or other air locker in the rear axle, it will be totally open when not in use and you will have an air compressor for things that you need an air compressor for, like filling tires or air mattresses.

My buggy has spool in the front and air locker in the back. I would do automatic locker or limited slip in the front and selectable in the rear, if not selectable in both, for what you describe.

If you are opposed to the air locker, then limited slip in both ends or locker front, limited slip rear.

 

[jk_surgeonfish]

I'll chime in on the locker question. In my personal experience, a selectable locker is best if you plan on any time in ice or snow.

 

[smokeyyank]

Think you have a good plan overall. I had 4.10s and 31s and it was a great combo, When I went to 33's it wasn't deep enough, especially in CO with our elevation. I'd put a 8.25 or a 8.8 in the rear and ditch the 35 entirely. People will say the 8.8 hangs too low on 31's but unless you're going over crazy obstacles it's a moot point IMHO. I had one on 31's and never had issues. Plus you get disc brakes and a stock LSD can be found. Front lockers are really dependent on use and funds. I've heard if you can only lock one do the front but that was mainly for rock crawling. I personally would rather have my rear locked if I only had one. Selectable are the best option as you choose when you are locked but obviously the most expensive. Personally, I'm not a fan of lunchbox lockers on a street driven vehicle. I have one in my WJ and it's mainly my camping/snow rig but driving on the road the ratcheting get's very old. In snow people say they all a problem but I've yet to have issues with the handling of mine. A torsen style would be my choice. Key for overlanding is simple and reliable.

 

[nyc98XJ]

Watch out with those 31 inch tires if you want to put them in the stock spare location. The pre 1997 models had a bit more room so you could fit a slightly larger tire. If you look at the go_jeep youtube that another wrote about a couple of posts up note that he doesn't have a last generation XJ.
The BFG you are looking at is around 30.5 inches if I recall correctly. In my 1998, my 29.6 tires just make it, I can't imagine stuffing something almost an inch bigger in there without touching the rooftop speaker.

Regarding lockers, I've always heard front selectable locker and rear Eaton TrueTrac.

 

[Evan03]

I think if it were mine I would do chromoly shafts and either detroit or grizzly in the front leave rear open since most your time is spent in 2wd on good roads.
Not even sure swapping a 8.25 or 8.8 in the rear is needed.
Id stay away from any diff that is cable eletric or air it will fail on you

4.10 gears sound perfect.

Not sure going to old man Emu will gain you anything. Maybe put good shocks on the 2" lift you have. Kyb monomax are good. In my opinion about the best your gona get over the counter.

A winch recovery gear might be better than a lift tires n lockers and probly lots less exspensive

Minimal to no lift.
Dont complicate with selectable lockers
If stuck drag winch line dont beat it up trying to get unstuck.

To me I think you were on track then the internet confused you.

Bone stock xj on small grippy tires n winch is the rig for you.

See how ive talked myself outa all the complicated mess of bs

Sent from my SM-G781U using Tapatalk

 

[maxbraketorque]

Watch out with those 31 inch tires if you want to put them in the stock spare location. The pre 1997 models had a bit more room so you could fit a slightly larger tire. If you look at the go_jeep youtube that another wrote about a couple of posts up note that he doesn't have a last generation XJ.
The BFG you are looking at is around 30.5 inches if I recall correctly. In my 1998, my 29.6 tires just make it, I can't imagine stuffing something almost an inch bigger in there without touching the rooftop speaker.

Regarding lockers, I've always heard front selectable locker and rear Eaton TrueTrac.

Yeah, I don't see how a 31" tire is going to fit in the stock location on a late model XJ. Mine still has a stock size spare, and it uses the entire available space. There's maybe 1/2" of space in front and behind the tire. Some room can be created by changing the rear seatback tilt, but I'm not sure that a 31" tire can be stuffed in there.

 

[RCP Phx]

In "lil sis" I carry a 31.50 in the factory location/mount with no problem!

 

[jeep ride]

I fit a 31 1050 in the stock spare location had to remove the metal bracket that the tire sit on moved the bolt that goes through the rim to screw the wing nut that holds the tire in place rear seat back didn't latch on that side tire rubbed on the sound bar a little the rear would close .

 

[nyc98XJ]

So what year XJ do you guys have @RCP_Phx ?
Pre 1997 had a bit more room and you really only need a bit more room to squeeze in a 31 inch nominal (30.5 inch actual) tire.
As @jeep_ride wrote, a 31 will rub on the sound bar and the rear seat back won't latch even after removing the floor bracket and the bolt that goes through the center of the wheel. I'm surprised the hatch closed but I guess there is a little give in the plastic hatch panel.
I'm happy with my approx 29.5 inch tires.

https://photos.app.goo.gl/cnN2nAtBbkiEapDi6

 

[nyc98XJ]

Tried to post a picture link
https://photos.app.goo.gl/cnN2nAtBbkiEapDi6

 

[RCP Phx]

So what year XJ do you guys have @RCP_Phx ?
Pre 1997 had a bit more room and you really only need a bit more room to squeeze in a 31 inch nominal (30.5 inch actual) tire.
As @jeep_ride wrote, a 31 will rub on the sound bar and the rear seat back won't latch even after removing the floor bracket and the bolt that goes through the center of the wheel. I'm surprised the hatch closed but I guess there is a little give in the plastic hatch panel.
I'm happy with my approx 29.5 inch tires.

https://photos.app.goo.gl/cnN2nAtBbkiEapDi6

"Big Bro" and "Lil Sis" are indentical 2000 Freedom's, I started on Big Bro when it wasn't even 2 weeks old!

 

[jeep ride]

Mine was a 98 model