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MJ Crawler

93K views 247 replies 58 participants last post by  cooleysix 
#1 · (Edited)
This vehicle is a semi-daily driver, meaning I have an FZJ80 that I drive most days, but I still drive this MJ to work once or twice a week when it's running. It has to remain streetable to an extent so I can drive it across the country to trails if desired.

Current Project: Shorten the bed, improve the departure angle, and shorten the wheelbase. Current wheelbase is 113", I prefer closer to the 101" that my XJ was when I had it.





Problem 1: My 57" long MJ springs hang out too far behind the rear wheels and don't fit my design goals.
Problem 2: I'd prefer to keep the gas tank underneath if possible to increase bed space, but will consider moving it to the bed.

Options:
1. 47" stock YJ rear leaf springs. Pros: Easy to setup, doesn't interfere with the gas tank even though the axle itself might. Cons: possible lack of articulation, rough ride. Any comments on long vs short leaf springs?
2. Radius arm rear coil suspension with panhard rod. I've read some that say these are OK, some that say these don't handle well. Pros: easy to setup, should ride good, doesn't interfere with exhaust or gas tank. Cons: off-road characteristics?
3. Parallel 4-link with panhard. Pros: better handling off-road than radius arms? stays clear of gas tank & exhaust
4. Double triangulated 4-link. Pros: best handling of all the options if setup correctly. Cons: Most difficult to setup, takes up all the room where the gas tank and exhaust would go. Where do most people route the exhaust when running a triangulated 4-link? From looking at it, I'd have to dump it under the bed, route it under the frame rail out the side, or drill a hole in the frame and route it out the side through that hole.


I will be cutting the frame rails right behind the crossmember.







I've just had all these options going through my head for a while now and would love to hear from you guys of any experience you have with this stuff.

Future projects: Install recentered H1 beadlocks, military 37" tires, and '79 F150 HP D44 front axle that I have already shortened to waggy width.
 
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#218 ·
I went ahead and ordered the full race head from 505 Performance, I just don't have the time to deal with an engine swap right now. I also ordered some different rear springs and some rear bump stops to fix the harsh bottoming out I get when I'm on a rough trail loaded down with gear. I got the new electric fan put in last weekend. I'm still trying to decide what to do as far as the exhaust goes, I'm leaning toward the $120 header on eBay, or just keeping the stock manifold, which would kill a lot of the performance from the new head. I just can't see spending another $400 on a fancier header.

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#220 ·
They came out of a Pontiac Grand Prix, not sure what year. I had to fabricate the mounts to get them in, and I raised the seating position for better visibility. I love the way they feel, but they were a pain to put in. The seats don't fold forward for easy access to behind the seat storage. Previously I had two door Cherokee seats in there, but they were two squishy and I just didn't like how they felt. They were also old and thrashed.

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#221 ·
I moved from Texas to Illinois last month. I have a 3-car garage to work in now, but it has no heat, only two 110 receptacles on a circuit that blows the breaker if I run space heaters on it, and it's pretty dark in there too. I'm currently installing a 100-amp sub panel, three 240 outlets (plasma cutter, welder, air compressor) on two 50-amp circuits, four more 120 outlets on a separate 20-amp circuit, and a lot more lighting. Once that's done I'll be back to working on the truck.

It has run a little hot ever since installing the new head and I noticed bubbles coming up through the radiator overflow, so I'm assuming my head gasket didn't seal up properly or I have a cracked block or head. When I went to put the transfer case in neutral so I could flat tow it here, it wouldn't go into 4x4 or neutral, so I have a transfer case issue as well. I'll check the shifter cable first to make sure that's not it. We want to do a trip all through Michigan this summer and to the upper peninsula as well, just camping and exploring the forests and trails, so it needs to be ready by then.
 
#223 ·
I got the 220 and 110 circuits done in the garage, now I can run my welder, air compressor, and plasma cutter all at the same time. I added a ton of lights as well. Then I had rotator cuff surgery Feb 19th, so I was out of commission for a while.
I tested the coolant to see if there were exhaust fumes in it. No fumes, so head and gasket are ok. Threw on a new radiator cap just because, no change. Pressure tested the system and it was seeping out near the upper neck where the upper hose connects. I replaced the upper radiator hose and it didn't fix the problem. Pulled the radiator, plugged upper and lower necks, pressure tested again. There are small micro cracks all around the neck where it is leaking out. This explains why it was running a little hot. The system would not pressurize. It also explains why I kept losing coolant even though it never leaked. Steam was escaping. The radiator I had was a Modine 2-row all brass/copper that I've run for 17 years on my previous XJ and then the MJ. I ordered a new radiator to solve the problem.
I pulled and opened the transfer case the first week of February, and noticed that the back collar was slightly damaged and had burrs all along one edge. I cleaned up that gear and put it all back together. Now I notice the rear output shaft won't come out far enough to put the round peg in it's hole that holds the speedometer gear onto the shaft. I tried to cinch it down with the impact gun and the yoke to get the shaft to come out to no avail. Opened the case back up and noticed I had screwed up the oil pump gear splines slightly when trying to cinch down the yoke to pull the shaft further out of the case. Disassembled it up and cleaned it up with the Dremel. Test fit the case together with no sealant, checked all the gears, everything worked, shaft was out far enough, etc. I pulled it apart, applied sealant, and re-assembled it. The output shaft wouldn't turn freely once it was re-assembled. I played with the output shaft, pushing it in and out to get it to align properly with the oil pump gear. Once it was aligned everything turned smoothly, but the hole in the output shaft for the speedometer gear peg was only halfway visible past the bearing, so the shaft needed to come out a tad again. I used the yoke to cinch it down a hair. I'm confident that the speedometer gear was lined up this time because before I couldn't see the hole at all. Once it pulled the output shaft out a little I was able to get the speedometer gear on, but now the output shaft doesn't turn freely, and if I turn the front yoke by hand it will turn but the gear inside is contacting and grinding against another gear. Are any of you guys good with the 03-06 NVG241OR (NV241J)? I've done multiple mods to 231C's and 231J's in the past, but never had these issues and it's kicking my butt.
 
#226 ·
I got a Factory Service Manual for the 2003-2006 TJ (including the Rubicon) and found the instructions for the 241OR transfer case. I also found some install instructions for a 2-low kit, and it referenced having it in 4-low when assembling it. I did that and was able to get the transfer case back together last night, which I needed to because my son took the 4Runner out and got stuck again. I needed the Comanche to pull him out. Once the transfer case was back in the Jeep, I wasn't able to get it into neutral or 4-low, the linkage appears to be hitting something. I'll still have to get that fixed, but I was able to pull the 4Runner out. You'll notice in the video I can't even go up a slight incline in high range, the 4-cylinder just doesn't have enough torque down low, even with the race head, purple cam, etc.

https://youtu.be/ZYZ2IDvvaHUhttps://youtu.be/ZYZ2IDvvaHU
 
#227 ·
Thanks Actionfab. I fixed the TC linkage problem. When I installed stock motor mounts it lowered the engine, which pivoted the transfer case up slightly, causing the 4wd lever to contact the edge of the transfer case enough to prevent shifting it into neutral or 4-low. I modified some Daystar poly mounts and installed those, which fixed the problem.

Next issue is steering. My steering shaft U-Joints are worn and need to be replaced. Steering box is worn again as well. I'm trying to get it ready for my trip this summer to Insane Terrain, Badlands, and four off-road parks in Michigan.

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#228 · (Edited)
I ordered Borgeson parts to create my own new steering shaft and finished that up yesterday. The parts are much beefier than the stock stuff I was running.



I got a new steering gear box (gotta love AutoZone Lifetime Warranty on that), and am waiting for a new lower steering column bearing to replace that as well. If there are other steering column components that are worn I'll replace them some other time. Either way my steering should be a lot better this time around.

I also started building a hitch carrier specifically designed for my new, larger cooler. The design goals are to keep it as small, compact, and tight to the body as possible. It also has to be able to take a hit or two without being damaged, and it has to have a tight fit in the bumper so it doesn't move around side to side as I'm crawling rocks.





A buddy of mine invited me to visit him near Toronto, so we might head that way after off-roading in Michigan. Does anybody know of any off-road parks or trails between Detroit and Toronto that I could hit along the way?
 
#229 · (Edited)
The steering shaft is in and I made slight improvements to the alignment. I just need to adjust the steering wheel straight. There is still a tiny bit of play in the steering, not sure if it's from the steering column or what, I'll have to mess with it after the trip.

I finished up the cooler carrier. Next up is the spare tire mount if I have time. I still have to grease all of my Ballistic joints and check all my fluids before the trip.









I have also been doing a lot of work to the wife's 4Runner to make sure it's ready for the trip as well. I replaced the wheel bearings on the front passenger side and I'm dialing in the alignment now. I will be selling it after this trip so I can start on my new project, a 2006 Expedition on 43s and one tons. One week left until the trip.

 
#230 · (Edited)
The trip was quite the adventure. We wheeled The Mounds, Twisted Trails, and Rocks and Valleys Off-Road Parks. We had a lot of fun, but got a small ding in the 4Runner driveshaft at the Mounds, which caused some vibrations on the highway. We then drove to Toronto and spent a week there. The day before we were supposed to leave, we were on the highway coming back from a day at the lake when the rear driveshaft pretzeled and broke loose from the rear axle, cracking the transfer case housing and output shaft, cracking the transmission housing in three places, breaking the ear off the engine block that the transmission bolts up to, and trashing the rear axle pinion seal. To make the story short, a fellow wheeler loaned us his trailer to get the rig back home, and we parted it out (the 4Runner).

Now on to the truck. The brand new steering gear that I put in right before the trip has tons of slop in the sector shaft bearing again after just one trip and I have death wobble bad. I couldn't find any looseness in the tie-rod ends or track bar ends. The tires wobble bad, so I put 10 ounces of dyna beads in each tire, but it didn't help with the death wobble. Does anybody make a heavier-duty bearing or bushing to replace the crappy sector shaft bearings that AutoZone rebuilds theirs with? I'm running the 98 Durango steering box. I'm trying to avoid swapping in a different model steering gear because everything is super tight in there with the hidden winch and custom front crossmember/bumper.
 
#232 ·
I believe west Texas offroad makes, or has someone else make, a new bearing. Pricey, but available. When I talked to them, they said there’s 2 different types of Durango boxes, a Saginaw and a china box. Bearing doesn’t fit china box if I remember correctly.
 
#233 · (Edited)
I'm looking into the sector shaft braces now, I didn't know those existed. I'd prefer just a metal sleeve that I can weld to with a bearing inside with the nut to fit in there perfectly. I haven't found that yet though.

My Durango box is an Autozone reman unit with a lifetime warranty, but after replacing it four times it's getting old.
 
#234 · (Edited)
Synergy Mfg makes a sector shaft brace for a TJ, and you can buy a replacement bearing and nut for their product, which I'm hoping will fit my Durango box. Then all I need is a 1.5" ID tube that I can cut a piece of to press the bearing into and build off of. I have some 2" OD .250 wall tube that I'll use for that. The part numbers are below.

SYNERGY MANUFACTURING SCE2012 JK/JKU/TJ/LJ Steering Box Brace Bearing
SYNERGY MANUFACTURING 806903-01-PL JK/JKU/TJ/LJ Steering Box Brace Sector Shaft Stud (Zinc Plated)

I also finally started on my driver-side rock slider, built a new tie-rod to replace my bent one, thinned out the interior wiring harness, installed a new blower motor (with housing), and installed a new dash.



 
#236 · (Edited)
I haven't updated this in a while, I did finish the sector shaft reinforcement, and the driver side rock slider. I moved the tie rod above the knuckle when I had to rebuild it last time. I also got rid of my military tires and wheels because of a constant death wobble. I have some temporary 35s right now. I will be replacing the tires with 37's eventually, but these are 17 inch rims, so I have a lot more options for tires now.

 
#237 · (Edited)
We have a family event that came up in Utah next month, so we decided to make a trip of it and we'll be spending some time in Moab. I bought a new set of 37s that I'll get mounted tomorrow.
3109779


I'm in the middle of an SAS on my Suburban, but it won't be ready in time for Moab. I have six kids, so we need another vehicle to drive in addition to the Comanche. Yesterday I bought a 2001 Grand Cherokee with lockers, sliders, RCVs in the front, a winch, and a 4" lift on 33s. It's barely streetable right now, so I'll fix it up, take it along with the Comanche to Moab and back, then sell it after so I can focus on the Suburban and Comanche again.

It should be a fun trip, we plan to run Pritchett Canyon, Behind the Rocks, Moab Rim, Poison Spider Mesa, Gold Bar Rim, Golden Spike, Cliffhanger, and we'll see what else we have time for.
 
#238 ·
I finally built a spare tire mount in the bed, no more ratchet straps needed. When I shortened the bed years ago, I welded nuts underneath with reinforcements welded to the bed floor to distribute the load over a wide surface and connect to the cross beams below the bed. That's what this is bolted to.
 
#239 ·
Spare tire is on there and the new tires are mounted. Time to see what else I can finish before the trip, like a new shifter boot to seal up the cabin, speedometer correction, and maybe get the tailgate on.



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#240 · (Edited)
Nobody makes a shifter boot for a Cherokee or Comanche 5-speed anymore, so I had to get a TJ one, which requires modifying the hole covering to give the Boot something to attach to. I had to remove the carpet to get that metal plate off. Once I removed the carpet, I saw how nasty and wet it was, and that the floor was rusting again. The passenger side had several rust holes and deep pits. So simply wanting to install a new shifter boot turned into cutting out and replacing floors, and spraying everything with rubberized undercoating. I'm leaving the carpet out. I like the sound deadening of the carpet, but I can't stand having to constantly mess with the floors due to rust.
 
#242 ·
We’re back in Illinois now. We only ended up doing Pritchett Canyon, Moab Rim, Kane Creek Canyon, and Cliffhanger due to multiple vehicle problems and breakdowns (mostly with the other vehicle we took). The video of Pritchett Canyon is below. .

I’m refining my shock mounts and muffler placement on the truck now.


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#243 · (Edited)
When I first set the shocks up on this truck, they were pulled from another vehicle that I had, and the eyes are slightly different. I blew the seals on the shocks during this trip, and got free replacements since they were under warranty, but they would not bolt up and I did not want to grind the sleeves down again. So I modified the shock mounts. A stock set of Ranchos will bolt up now.






Since I had the bed off, I decided to upgrade my roll bar tie-ins. Years ago I built the one below with the round tube supporting it, before I had the rock sliders.




This is my latest rendition. I boxed it all in and tied in the frame and Sliders to the roll bar mount.




One of the gas tank welds developed a crack during the trip as well. JB Weld steelstik held up from Utah to Illinois. I will build a new gas tank at some point since I want one slightly larger. I haven't decided if I want to spend the money to upgrade my welder to a multi-process machine, just build one out of steel, or have someone build it.


 
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