Bench Racing; TJ Crawler build

Greg

I run a tight ship... wreck
Admin
So this is just an idea at this point, nothing more.... probably won't be acting on it, but wanted to write the idea down and see what it looks like.

After attending some of the RME runs, I feel like i need something more capable to keep up. Not going to take the Gladiator or CJ2a on Hanging Tree, Pritchett, etc. My old RME TJ that I built years ago was fun, but quite the project. IMO the TJ is a great platform for a capable crawler and they're getting cheap. I'd love to build another one, with a slightly different direction and possibly lighter with smaller tires. I think with the plans, it should all be pretty well balanced. The axles would do the job, if built up right IMO. Here's my thoughts;

Drivetrain; VW TDI ALH with mods and a tune, putting out 300 ft/lbs - AW4 transmission with Winters shifter and full manual control - Dana 300 with 4 to 1, HD outputs, Behemoth case and Behemoth Flip Kit for driver drop.

Axles; JK Dana 44's, trussed, sleeved, geared & locked. RCV shafts would be nice, but $$$. I think good 4130 shafts and high quality u-joints would do the job. R&P seem to be up to the task if I stayed on 37's. Beefing up the front housing & knuckles would solve most strength issues... or just buy a Tera44 like I did for my JKU.

Suspension; Stretched rear axle for 102"-104" wheelbase - 3 link in front, triangulated 4 link out back. - ORI Struts, won't need air bumps, limit straps. Keep it pretty low, but not crazy low. Shoot for about 3" of lift, maximum.

Tires; Possibly 2 sets of tires, 37" BFG Krawlers Red Labels for hard trail tires, Blue Labels for everything else. Beadlocks of some sort.

Steering; Keep steering box, run hydro assist so it's road friendly.

Body, Frame & Cage; Fiberglass high hood, no fenders, back half rear frame, build full cage. Probably boatside the tub, either comp. cut the rear quarters or more wheelwell back to match tire placement. Fuel cell behind the rear seat.


So that's what I'm thinking.... I could still have doors, heater (possibly A/C?), license plates and the things that make a rig comfortable, but be capable of running the harder trails without too much fear of damaging it or breaking parts. The TDI would be killer on the trail, IMO. Lots of torque down low, good power at higher RPM when momentum is needed, not use much fuel compared to a gas engine.

Anyway.... that's on my mind today. :D I do have the TDI, AW4 and D300 sitting in the shop. As well as enough material to build a 3 link for the front end.
 

Mouse

Trying to wheel
Supporting Member
Location
West Haven, UT
You mention a steering box to make it street friendly, so I was surprised to see you include an in-the-tub fuel cell. I consider a fuel cell inside not street friendly. Including a Genright tank, you can modify a stock tank for more rear stretch. Plus d44s take less room when considering the tank
 

Greg

I run a tight ship... wreck
Admin
I like that you think 37" is a 'smaller tire'! :rofl: :rofl: :rofl:

In comparison to my old TJ on 40's, 37's ARE tiny! But they're also just enough tire for the harder trails, IMO. 40's would be great, but too much for the axles. I really don't want to go with Tons again, due to the $$$. I could do Super Duty axles and not have to worry about housings, shafts, etc?

IMG_3294-X2.jpg



You mention a steering box to make it street friendly, so I was surprised to see you include an in-the-tub fuel cell. I consider a fuel cell inside not street friendly. Including a Genright tank, you can modify a stock tank for more rear stretch. Plus d44s take less room when considering the tank

I figure that the rear axle will end up living where the front edge of the factory tank sits. I don't mind a fuel cell in the tub, I don't plan to run a full top so fumes in the cab wouldn't be terrible and it would be diesel, so at least it's not as flammable as gasoline. My old TJ had a fuel cell behind the seat. I like the GenRight tanks, but they're $$$$.
 

mbryson

.......a few dollars more
Supporting Member
go Super Duty axles (there's a YJ tub/body on KSL for $1400---it's yellow--more $ than I thought)

YJ

TJ
 

Hickey

Burn-barrel enthusiast
Supporting Member
For the amount of money and work, I would choose Super Duty axles over the JK axles. Maybe use TNT's steering box rotation kit to stretch the front a little and protect the box itself more better.
 

Greg

I run a tight ship... wreck
Admin
I like the idea of raising the floor in the rear for fuel tank clearance, but still have the ability to carry a cooler and tools in the back.

I figured a 15 gallon fuel cell behind the rear seat would leave plenty of room for a cooler, tools without the seat in place or a rear seat when needed. I'm not sure a stock tank would fit with a back-half kit. I really disliked how the factory rear frame hung down in the back, after moving the rear axle back on my old TJ and wouldn't keep it, if I built one again.
 

N-Smooth

Smooth Gang Founding Member
Location
UT
Definitely just do SD axles. It’ll be cheaper, stronger and I’d wager not a whole lot heavier once you beef up the JK axles.

I’d also skip the ORI’s if it was me. Air shocks will do everything you want and are cheaper, lighter and easier to get your hands on.

Oh and just do 4D’s. They’re the new 37’s ?


My dos pesos
 

RockChucker

Well-Known Member
Location
Highland
Sounds somewhat familiar. My thoughts (I might be a little biased ;))

My original plan was for 37s. I didn't need a bigger tire. One trip up helldorado changed that thought. But a 40 is much bigger to squeeze in and I had to raise my highlines so as not to limit my uptravel.

My original plan was also a 102-104" wheelbase. Seven, maybe 8 inches is all you can stretch in the rear without a comp cut. That would have been a 2-3 inch front stretch. For the effort of moving the steering box, it made more sense to move to a scout 2 or fj60 box that mounted outside the frame with a forward swinging pitman arm. At that point, 108" makes sense. Boatsides are awesome. And a lot of work.

JK axles have their merit, but you'll be cheaper to just put in a set of 05 plus SD axles. Every time I see JK (really any linked Jeep) axles for sale, I can't help but wonder if they are gold plated. $600-800 will get you a pair of SD axles. $800-1000 will get you just a rear JK axle from what I've seen. And with custom suspension, they wouldn't really be that much different for the amount of work required.

I haven't had any problems with my tank mounted behind the seat. Even with a top (that hasn't been on for a couple years). I would put the tank right behind the driver seat if you aren't doing a rear seat. Makes accessing your cooler and tools way easier and keeps the weight more central.

I'd do coilovers rather than struts or airshocks. Personal preference based on observation. And I really like my tuned coilovers. Saw a TJ last time I was in Moab with struts. He was touting not needing swaybars or bumpstops. That thing looked super unstable on the couple large climbs I watched him attempt. Much like a slinky. Maybe it needed tuning? If you aren't going to ever go fast, you really don't need bumps with coilovers either. And there are things you can do to the shocks that can make it so you don't use bumps and still have decent bottom out resistance.

I've never run krawlers, but did almost buy a set of blue label 39s when it took 6 months to get km3s. Also to note, my 39" km3s are about 38" with 25 psi in them. Much shorter than that with lower pressure.

All in all, I think my rig is about as close to a swiss army knife as you can get. It does a lot of things pretty well. It crawls well, can go decently fast in the rough stuff, drive down the highway at 70-80 mph and I can put a top on and crank the heater to stay warm in the winter. Defrost is magical. The hyrdoassist isn't my favorite, but I have some things I'm going to try this winter to try and improve it. May end up with a double ended ram among other things.
 

LJTim

Active Member
Location
Herriman, UT
I would love to start a fresh dedicated crawler project out of a TJ or YJ. Many of your initial thoughts are similar to mine.

I have a JKR44 in the front of my LJ. It holds up to 40's. I have it trussed, sleeved, gussets, RCV's and Cryo treated the 5.38 gears with an Ox air locker. It took a lot of $ to build it up like that, but I don't baby it. Truthfully, the only way I would recommend JK axles is if you get a great deal with the lockers, knuckles and brakes included. All that crap adds up if it wasn't included in the JK housing. Otherwise you'll spend the same amount of $ and have a tougher set of axles out of a SD. I do have a friend selling a set of JLR 220 axles which are awesome! He ended up with 2 sets, so one is up for grabs for $4k (although his set does not include brake calipers).

Dave has me intrigued with what he's saying about the steering box and front end stretch.

I love ORI struts if they are tuned right. If they aren't, they can crash your jeep in a hurry. I wheel with a lot of guys at SH that swear by ORI struts, and when I'm with them, I swear by them. But I have had strangers in some of my groups that end up super tippy. On the other hand, I am regularly on the trail with guys with coilovers that the front end unloads all the time. I'd rather have stock short arms than have the front end loose traction the way most coil over rigs do on a super steep climb. But then again, that probably has a lot to do with tuning and proper springs too. I am no expert on struts and coilovers, I just know either way will take you a lot of time, trial and error to get them dialed in. I'm not yet convinced to ditch my shocks and coils.
 

Pile of parts

Well-Known Member
Location
South Jordan
Wish I were better about build threads. My info may not be helpful anyway, since mine is based on a YJ. However, regarding the steering box relocation, I couldn't find much info so I just did it. I had already stretched mine 2" in the front when I was on leaf springs. Steering box in factory location. As I have been converting to links, I decided to stretch it another 2" and this time had to move the box. I cut the factory tube crossmember out and replaced with 2x4 tube welded to the end of the frame horns. I then plated the frame horns with 3/16", slid the box mount forward, marked, drilled, sleeved and welded. I had to notch the bottom corner of the grill for the lines to run to the box. There was some thinking and researching involved in getting all the right parts and clearance but really not too difficult on a YJ. I did look up the TNT stretch kit (after reading this thread) and it seems to be what I did - in kit form. However, it has the added benefit of rolling the box up and out of the way. I will just build a steering box skid plate. Anyway, here is a picture.

IMG_20191021_205822452.jpg
 
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