AreWeThereYet Posted July 10, 2025 Share Posted July 10, 2025 A buddy of mine rescued this Comanche with some cool ideas in mind, but ended up pursuing other projects. After I started casually browsing rock crawlers, several hints were dropped that the MJ would be a great candidate, and I couldn't resist. From what I've been told and am able to find out, it's a 1987 base model short bed that came with a 4.0 and a 5 speed manual. Currently it has a 4.0 out of an 88, automatic AW4, NP231, and a low pinion D30 from a YJ on leaf springs up front. It runs well, shifts, and the 4x4 engages, but it's still a project. VIN Decoding. Link to comment Share on other sites More sharing options...
89 MJ Posted July 10, 2025 Share Posted July 10, 2025 Looks like a good project. What do you have planned for it? Link to comment Share on other sites More sharing options...
AreWeThereYet Posted July 10, 2025 Author Share Posted July 10, 2025 The goal is to get it on the trails by the end of the year. I'm currently regearing the axles that will go under it to 5.13. The front is a HP Dana 30 trussed with WJ knuckles/ brakes, high steer, 4340 shafts, Spartan locker, and Warn lockout hubs. Rear is a 29-spline Chrysler 8.25, 4340 shafts, Spartan Locker, and will be converted to disc brakes. Going to run 35s for now, build basic bumpers and sliders, 3-link the front, put coil springs back on it then just new shocks/mounts in the rear. It has a set of doors and a bed from another truck, but the bed is too nice for off-road, so I'll try to sell it and intend to build a simple flat bed similar to the one below. Dana 30 Flatbed idea Doors and the short bed. Link to comment Share on other sites More sharing options...
AreWeThereYet Posted July 10, 2025 Author Share Posted July 10, 2025 I got to drive it a bit last week after I found a deal on some Method MR 105 beadlocks with decent tires. 2936291304904052732.MP4 Link to comment Share on other sites More sharing options...
89 MJ Posted July 10, 2025 Share Posted July 10, 2025 I think you've got a great plan there. Especially putting a 3 link in the front and ditching the leaf springs. Link to comment Share on other sites More sharing options...
Big_Mark Posted July 10, 2025 Share Posted July 10, 2025 89 MJ beat me to it, leaf springs are not good for rock crawling, unless you like to hammer down all the time, which has it's place Link to comment Share on other sites More sharing options...
AreWeThereYet Posted July 22, 2025 Author Share Posted July 22, 2025 Made a little progress and got the locker swapped to the new carrier and put the new ring gear on. Link to comment Share on other sites More sharing options...
ThatJeepGuy Posted July 24, 2025 Share Posted July 24, 2025 The traction bars on the rear (or what's visible of them atleast) is intriguing. Looks like a great start regardless the missing bits Link to comment Share on other sites More sharing options...
AreWeThereYet Posted July 24, 2025 Author Share Posted July 24, 2025 6 hours ago, ThatJeepGuy said: The traction bars on the rear (or what's visible of them atleast) is intriguing. Looks like a great start regardless the missing bits Thanks. The rear bars are Definitely intriguing, but a lot about this truck is. For now they’ll stay, and I’ll find a way to mount them to the 8.25 that’s going in the rear. Link to comment Share on other sites More sharing options...
89 MJ Posted July 24, 2025 Share Posted July 24, 2025 Seeing that pic of the rear suspension has me thinking there probably was a bad axle wrap problem. Those spring perches are awfully tall, but good for a little bit more lift. Link to comment Share on other sites More sharing options...
AreWeThereYet Posted July 29, 2025 Author Share Posted July 29, 2025 I was poking around over the weekend and found the engine date code: 801M20. If I understand correctly it was built January 20th, 1988 which means it came out of another Jeep, probably whatever YJ the front axle is from. Ultimately it doesn't make a difference other than I know someone put a good drivetrain in it at some point, just unsure of the mileage. Link to comment Share on other sites More sharing options...
89 MJ Posted July 30, 2025 Share Posted July 30, 2025 On 7/29/2025 at 4:59 AM, AreWeThereYet said: If I understand correctly it was built January 20th, 1988 which means it came out of another Jeep, probably whatever YJ the front axle is from It would’ve had to be from another XJ or MJ. The YJ didn’t get the 4.0 until 1991. Link to comment Share on other sites More sharing options...
AreWeThereYet Posted December 23, 2025 Author Share Posted December 23, 2025 After a busy few months, some setbacks, and my ability to overthink and underthink everything, I now have the front Dana 30 regeared to 5.13 with a Spartan locker. Here's where my pattern ended up. Might be a tad deep, but I don't mind. It definitely feels good to make real progress, and on one of the "more challenging" parts of the project. I did the final assembly, and now it will sit until I regear the Chrysler 8.25 for the rear. It will also be a big undertaking to get the axle under the front. Someone in this MJ's history cut up and welded on a bunch of mess to the front to add leaf springs. Most of it will be cut out, and I'll fab up simple spring towers, but the whole front bumper area may take some creative fab work. On a side note, if you order from Revolution Gear, be wary of their master install kits for the D30. I ended up not having all the parts needed, and they didn't carry the missing baffle and oil slinger. To their credit, the customer service was great and responsive, but didn't have a resolution for me, and basically said because they don't pack their own install kits, they have no control over it. The ring and pinion were great, it was just disappointing to order a kit that was described as having everything needed, then finding out it doesn't with no resolution other than to order missing parts from another vendor. Link to comment Share on other sites More sharing options...
JoeLAW Posted December 30, 2025 Share Posted December 30, 2025 Nice man, good thing you're making progress. I almost always order most of my differential related stuff from East Coast Gear Supply, usually way better prices than anywhere else, fast shipping and superb customer service. Funny thing I was thinking of doing a very similar setup of traction bars for my truck, but I'm still a bit on the fence.. It would be nice to see how yours work on the back specially when flexing it out. Link to comment Share on other sites More sharing options...
AreWeThereYet Posted December 30, 2025 Author Share Posted December 30, 2025 16 hours ago, JoeLAW said: Nice man, good thing you're making progress. I almost always order most of my differential related stuff from East Coast Gear Supply, usually way better prices than anywhere else, fast shipping and superb customer service. Funny thing I was thinking of doing a very similar setup of traction bars for my truck, but I'm still a bit on the fence.. It would be nice to see how yours work on the back specially when flexing it out. Thanks, it's definitely good to have some progress on this. ECGS is definitely on my good vendor list along with Barnes 4wd. The more I think about it, the less likely I am to keep the rear traction bars. I don't do anything high-speed, and don't really want them hanging up on stuff. It may also not mount well with the 8.25 rear axle that I'm going to put in, and definitely don't plan to do work to make them fit. Link to comment Share on other sites More sharing options...
Big_Mark Posted December 30, 2025 Share Posted December 30, 2025 You should keep some kind of track bar in the rear, if only to control axle wrap, as 89 MJ pointed out, they were likely installed to control that very thing. Don't think "traction", think of it as "Control". When I went SOA on my CJ8 I went through 2 sets of rear leafs, they turn into "S" shapes or break, or both LOL. Once I added a track bar that problem went away. The condition where this happens is when you get your front end "up" (on a ledge, log, whatever) and you start bumping to get the rear end up, it puts all the weight and torque on the rear axle, making it wrap. Additionally, you can break a driveline U-joint which is a different level of suck. Anyways this is my free advice YMMV HAMMER DOWN Link to comment Share on other sites More sharing options...
Big_Mark Posted December 30, 2025 Share Posted December 30, 2025 This is more or less what I had, one anti-wrap ladder and my woes went away. I had Dana 60s 6:12 gears and 42" Iroks and the problem never happened again Link to comment Share on other sites More sharing options...
AreWeThereYet Posted December 31, 2025 Author Share Posted December 31, 2025 13 hours ago, Big_Mark said: You should keep some kind of track bar in the rear, if only to control axle wrap, as 89 MJ pointed out, they were likely installed to control that very thing. Don't think "traction", think of it as "Control". When I went SOA on my CJ8 I went through 2 sets of rear leafs, they turn into "S" shapes or break, or both LOL. Once I added a track bar that problem went away. The condition where this happens is when you get your front end "up" (on a ledge, log, whatever) and you start bumping to get the rear end up, it puts all the weight and torque on the rear axle, making it wrap. Additionally, you can break a driveline U-joint which is a different level of suck. Anyways this is my free advice YMMV HAMMER DOWN I appreciate the input; it's definitely something to consider. I'll have to figure out if these are worth keeping when I'm ready to start swapping the axles. I also don't trust (or understand) a lot of the previous fab work on this truck, even though I'm sure mine won't be much better. Sounds like you had a pretty nice setup, especially running 42s. Link to comment Share on other sites More sharing options...
Big_Mark Posted December 31, 2025 Share Posted December 31, 2025 Controlling axle wrap helps get the traction to the ground, otherwise you start wrapping and bouncing, when you start bouncing, ya start breaking sh*t FYI I'd run those, as long as the frame mount has some kind of additional plating to spread the load of the tourque on them. Otherwise you'll end up breaking the frame. So back in the day I was "the Scrambler Guy" in my group. One of my wheeling buddies "Jeepmauler" was the Cherokee guy. he swore by attaching a plate of steel to the unibody (in his case) by sandwiching the body between the 1/4" plates he custom cut to fit. Places like the floorboard where the A and B pillars connected to for instance, and later various versions of antiwrap bars, rods etc. He finally nailed it all when he scratch built a tube buggy thing lol. Anyways like I said this is free advise from an old timer, hopefully it helps! Enjoy brother! Link to comment Share on other sites More sharing options...
JoeLAW Posted January 4 Share Posted January 4 On 12/30/2025 at 4:25 PM, Big_Mark said: This is more or less what I had, one anti-wrap ladder and my woes went away. I had Dana 60s 6:12 gears and 42" Iroks and the problem never happened again How was your frame side mount on this? Was it solid, or more like a shcakle type? Link to comment Share on other sites More sharing options...
Big_Mark Posted January 5 Share Posted January 5 On 1/3/2026 at 6:28 PM, JoeLAW said: How was your frame side mount on this? Was it solid, or more like a shcakle type? I welded a plate to the inside of my driver side frame rail, it was about 10" long and the height of the frame. to that I mounted a shackle/bracket to it, then from that shackle a HEIM joint, and two HEIM joins at the axle bracket. I think I might have some photos but will need to dig deep to find them, lol Link to comment Share on other sites More sharing options...
AreWeThereYet Posted January 11 Author Share Posted January 11 Made some progress today, drained and cleaned out the fuel cell, then put in a few gallons of ethanol free with some fuel treatment. It wasn’t too bad with only a little bit of old gelled gas and barely any sediment. I noticed a new sticker was added to my truck, and I am not fat. After that I pulled the 8.25 rear out and started cleaning it up. Managed to pop the yoke off the pinion when I was knocking one of the perches off and drained half the diff onto the floor. By the time I wrapped up I’d cut off the old leaf perches, started on one of the shock mounts, and had a raging headache from the nasty fuel fumes from earlier. Link to comment Share on other sites More sharing options...
AreWeThereYet Posted Friday at 01:53 PM Author Share Posted Friday at 01:53 PM Took a couple of videos using a plasma cutter for the first time, if you look closely, you can see my smiley Comanche in the background. This will definitely be nice to have access to when it comes time to start cutting up the front end. Here's a couple of shots of the front for a better perspective Link to comment Share on other sites More sharing options...
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