Questions/Help with my TJ build

[Jason4x4]

Hello all. I'm in the process of putting together parts for a build on my '06 TJ and I'm looking for some advice. Currently I have a 2" RE budget lift and 32" Mud Terrains. For reference, I have the stock Dana 30 front and stock non-Rubicon Dana 44 rear end.

I guess the best place to start would be to tell you my plans and see if there is anything you all might disagree with or think I should do differently.

My goal is to clear 35" tires and be able to run "Black" trails without issue. Also keep in mind that while my Jeep is NOT a daily driver, I still want to keep it pretty comfortable on the road as well. To that end, here is my current thinking:

1) Upgrade to 4" short arm kit. I already have 4" Skyjacker springs and shocks (maybe not the best but I already bought them so I'm going to have to live with it). I plan on purchasing a full set of control arms from either Rough Country or Rusty's, all adjustable with flex joints. I also plan on adding adjustable track bars. I still need to pick up extended brake lines in addition to all of this, and I'm going to add a Skyjacker steering stabilizer while I'm at it.

2) Upgrading to the 4" lift, I'm going to go ahead and bite the bullet and upgrade to a SYE instead of another transfer case drop. I figured since I'm going to mess with the transfer case anyway, I might as well do a tummy tuck, with a high clearance transfer case skid. My research into this indicates that this will probably require a 1" body lift, so final lift count is 4" suspension + 1" body lift. Will this adequately clear 35" tires?

3) If I'm going to run 35" tires, the gearing charts I've looked at say that I won't be very happy with my stock 3.73 gears, so I plan on going with some 4.88 gears. If I'm going to be pulling my diffs apart, I might as well get some lockers, right? Those will come in handy on the black trails anyway . So I'm thinking I'd rather have something that locks positively as opposed to a limited slip, and I've been looking hard at OX lockers, since it appears that their pricing is competitive with ARB and I would not have to worry about messing with an onboard air system at this time. Since I'm planning on doing all this anyway, I might as well upgrade the axles, so I'm toying with the idea of upgrading from 27 spline to 30 spline axles in the D30...not sure if it would be worthwhile to upgrade the D44 or not. Thoughts?

So anyway...this is something I'm going to be working on gradually over the next year (or two...or three ) but I've given it a lot of thought and I think I have a good plan. Now it's your turn to tell me I'm an idiot and why I shouldn't do this and/or where I've screwed up.

 

[AA-CJ7]

A 4" suspension with a 1" body lift should be enough for 35's. If you have any contact you can fiddle with the bump stops or trim the fenders. One word on your choice of lift kits; there are suspension systems and there are lift kits. A suspension system will keep your tires in contact with the terrain, a lift kit will allow you to run larger tires. There is a huge difference. I would reconsider your choice here. I would also go long arm.

4:88's are a good choice for 35's and you'll need a 39t speedo gear. Your present axles will work fine for 35" tires. I would look at the 'Super 30' kit for the front. It come with everything you need. I've run ARB's for 10 years and never had a problem. The OX system is good also, but can be tough to shift at times. I would go with Superior shafts for the D44.

Two other items you should think about are your brakes and steering. EBC yellow pads will make a noticeable difference. If you need more braking, call Vanco. You'll also want to add a Currie tie rod kit and an in-line cooler for the pump.

Obviously this is not going to be cheap, but when you're finished you'll have a very capable and reliable Jeep.

 

[Jason4x4]

A 4" suspension with a 1" body lift should be enough for 35's. If you have any contact you can fiddle with the bump stops or trim the fenders. One word on your choice of lift kits; there are suspension systems and there are lift kits. A suspension system will keep your tires in contact with the terrain, a lift kit will allow you to run larger tires. There is a huge difference. I would reconsider your choice here. I would also go long arm.

I'm a little confused - Are you saying I should reconsider going with a short arm instead of a long arm, or is there some other mistake I'm making?? Thanks for the input and the steering/brake upgrades will definitely be on the list. Also, are you talking about an in line cooler for the power steering pump or something else? Thanks again.

 

[AA-CJ7]

Unless I'm reading it wrong your post says "Upgrade to 4" short arm kit". A long arm kit will work better everywhere.

35" tires will make your PS pump work harder and it will produce more heat. An in-line cooler will help your PS pump live longer.

 

[xjmarc]

35s are at the limit for the front D30 so before you spend the money to regear, lock and swap shafts you might look into an axle swap. I made the mistake of building a 30 and 35 (shafts, lockers and gears) and ended up yanking it all out and putting in bigger axles. Wish I had just started with the bigger ones, would have been a whole lot cheaper. We built a TJ on 4" with 35s and didn't have any clearance issues and it was short arms and rode pretty good.

 

[Jason4x4]

Unless I'm reading it wrong your post says "Upgrade to 4" short arm kit". A long arm kit will work better everywhere.

Yes, you understood me correctly. I don't disagree that a long arm would work better, but (correct me if I'm wrong) it would be a lot more expensive and a lot more work to install. I'm trying to determine if it would be worth the added expense. I guess my question is, I dont doubt that a long arm would be "better", but exactly how much better? I'm trying to justify the cost.

 

[Jason4x4]

35s are at the limit for the front D30 so before you spend the money to regear, lock and swap shafts you might look into an axle swap. I made the mistake of building a 30 and 35 (shafts, lockers and gears) and ended up yanking it all out and putting in bigger axles. Wish I had just started with the bigger ones, would have been a whole lot cheaper. We built a TJ on 4" with 35s and didn't have any clearance issues and it was short arms and rode pretty good.

Interesting. I wouldn't be opposed to swapping in a D44 front if the price was right, I'm just thinking that, assuming of course that the D30 with upgraded shafts could reasonably handle the load it would be a lot cheaper. It's definitely something to think about.

 

[xjmarc]

If you do build a D30 find a HP out of a XJ. Direct bolt in and a slight strength increase since you are riding on the drive side of the gears instead of the coast. Your axles, bearing and brakes will swap over.

 

[Jason4x4]

If you do build a D30 find a HP out of a XJ. Direct bolt in and a slight strength increase since you are riding on the drive side of the gears instead of the coast. Your axles, bearing and brakes will swap over.

Ok, dumb question. What is the HP??

 

[xjmarc]

High pinion, you currently have a low pinion. The HP would also decrease front driveshaft angles.

 

[Jason4x4]

Ok, I have been doing a little research today and the information I seem to be finding indicates that a D30 front axle unlocked can only handle 35" tires for "moderate" wheeling. With a locker the information I am seeing suggests not going larger than 33" with a D30. Can anyone confirm this? And this being the case, where would be a good place to find a D44 front? Anything wrong with buying used seeing as how I would be replacing most of the guts anyway (installing the OX locker and most likely R&P unless it happens to already have 4.88 gears in good shape)?

 

[xjmarc]

Find one out of a wagoneer, it's the same width all you need is the 4 link brackets. Someone makes a truss with everything on it just don't remember who. Someone on here does. Rubicon Express and Rustys make a full kit with all the brackets or you could go the route I did and take the ones off another axle (don't recommend it) just replace the lower control arm brackets if you go that route. The factory ones are basically sheet metal.

 

[AA-CJ7]

When they're both wheeled hard, a D44 has the same limitations as a Super 30. They both will handle 35's but not hard wheeling with 37's.

I had a D44 with Superior axles, ARB and 37" MTR's. I constantly broke chromoly axle shafts, U joints and knuckles.

The Super 30 kit comes with 30 spline Superior shafts, your choice of lockers and gear ratio's and will hold up well to 35's.

 

[Ggg]

I agree with all of what has been said up to where a 44 and a super 30 have the same limitations. Maybe I misunderstand what was said, I take that to also mean they have the same strengths. Not trying to argue, just a different opinion. Also I am not talking about the junk front 44 from a rubi.:roll: A real 44 (full size) has bigger brakes, bearings, R&P, thicker tubes, etc. Yes the alloy axles go a long way in helping a 30 last, in fact that is the only way I would recommend 35's on a 30 is with alloy axles otherwise I say it is limited to 33's with the stock shafts. Of course a LOT has to do with the type of wheeling, you can run some pretty big tires on some small axles in the dunes as compared to hard trails or rocks.

 

[jps4jeep]

I dunno, I have the same front axle set up, D44, but 4340 Youkon shafts, ctm's, detroit bla bla bla, and I have yet to brake a shaft. I actually split the pinion yoke in half before the shaft broke with tires in a locked up situation.

But...

If it were me, and I could do it again, I would skip the 1/2 ton axles and go straight to 1 ton. I am not sure what black trails are or how they fit into the difficulty equation, around here we have, in order of difficulty, Green, Blue, Black, Red. 35's and two lockers should be able to get through the trail with a couple tugs or pulls. I run our Black and red trails and I am the smallest guy.

I echo the System instead of a Kit, they is a difference. when you get to harder trails, your tires will not limit you, I find your wheel base does. If I were you, I would run the RE extended wheel base system.
Rubicon Express, Inc.

Take the front fenders off, slap on some 36" iroks, polish the crap out of the front and rear axle and go with that. you will see the short comings of the D30, after a year of replacing front shafts everyother trail ride, use the same suspension system, and swap in some 1-tons and run some 37" reds

 

[Jason4x4]

Still doing some D30 vs. D44 research, and I've come up with another question: Is the stock D30 standard rotation or reverse rotation??

 

[xjmarc]

The low pinion is standard rotation and the high pinion is a reverse cut gear but turns the same direction. Your TJ has the low pinion. Only YJs and XJs till mid 99 got the high pinion.