New Axle Advice for 35s

[The06LJ]

Ok, so first of all, the state of the build: It's an 06 LJ 6spd, and I've got it on 35s and 17" black rhino wheels for the last year or so. I clear them with MetalCloak overline fenders and 2" lift. Now its been a 3rd vehicle for me, and so the lack of power, under whelming brakes, and tire rubbing the steering box bolts in a tight right turn has been livable. The plan has always been to build a strong jeep capable of long cross country trips, with occasional moderate wheeling. I was planning to replace the front Dana 30 with a Dana 44, Locker (Eaton E Locker) and a BBK, and then re-gear (4.56), upgrade shafts and lock (also Eaton E Locker) the rear Dana 44. I've been driving the Jeep more and more recently and I'm finally fed up to the point where I'm ready to pull the trigger on this little project. The axle i have my eye on is the Dynatrac ProRock44, with all the goodies they offer.

Now i have already ordered a Super 16 BBK from Mr. Blaine, because i tend to drive aggressively, and always like to build bigger and better than i think i need. But for the Axle, it was recently suggested to me (by people I do not really know or trust) that i should find an axle slightly wider to fix the tire rubbing the bolt issue. also that i should replace my unit bearings with new ones from Timkin so that when i bolt this thing in, its all new from the T-Case to the wheels. I'd really like this to be a buy once, cry once scenario. I recognize that I know just enough to be dangerous, and so if any of you have any advice on a different route, or things that should be done "while I'm in there" id love to hear it.

 

[Jerry Bransford]

The front axle seldom sees more than about 50% of the load the rear axle sees on a regular basis. For that reason and when running 35's, there is absolutely (!) no need to replace your front Dana 30 with a Dana 44. Simply replace its carbon steel 27 spline axle shafts, both inners and outer stub shafts, with 4340 chromolly axle shafts. With those shafts your front axle will be more than up to 35's, a locker, and doing the toughest trails your Unlimited is capable of doing. Really.

4.56 will not be enough gear for 35's, really, you need to go 4.88. Refuse to be talked into 4.56 by the sales guys at your local 4x4 shop who usually drive big trucks with V8 engines.

For your tires rubbing you can add a washer or two under each of the two steering stop bolts screwed into the knuckles. That will not restrict your turning radius enough to notice, it will still turn on a dime. I never bothered removing mine after getting wheels with reduced backspacing that would have stopped mine from rubbing.

 

[The06LJ]

I probably should have mentioned the LJ plan includes a very significant power increase in the next 18 months or so. Hence my desire for an overbuilt front axle, also, the long term plan will likely include a Dana 60 in the rear.

it looks like the 4.88's will cost me about 200rpm at 75 over 4.56s. I know that's not a huge difference, but in the multi-thousand mile trips I'm looking at in the next couple of years, that sounds like it might not be worth it, especially when I'm used to 3.73s now.

i just figured that 4.56 would be a nice middle ground, i was even thinking that it woulda be ideal if i could find some old-school 4.27s

 

[Jerry Bransford]

I probably should have mentioned the LJ plan includes a very significant power increase in the next 18 months or so. Hence my desire for an overbuilt front axle, also, the long term plan will likely include a Dana 60 in the rear.

it looks like the 4.88's will cost me about 200rpm at 75 over 4.56s. I know that's not a huge difference, but in the multi-thousand mile trips I'm looking at in the next couple of years, that sounds like it might not be worth it, especially when I'm used to 3.73s now.

i just figured that 4.56 would be a nice middle ground, i was even thinking that it woulda be ideal if i could find some old-school 4.27s

You will hate the 4.56 ratio, I recommended 4.88 for your 35's for a reason. The rpms with 4.88 gears will NOT (!!!) be too high on the highway, that is the ratio you'll want for the highway for 35" tires. When ratios are recommended here they are generally always made with highway rpms in mind since 4Low takes care of the offroad rpms. And even with a far more powerful engine the 4340 axle shafts will be way more strong enough for 35's. You absolutely do not need a replacement axle for 35" tires.

But it's your decision, all we can do is offer recommendations based on our personal experience. And I do have personal experience with all of those recommendations. Like after breaking a front Dana 30 factory axle shaft on Sledgehammer in Johnson Valley with 35's and a locker, I replaced the shafts with 4340 27 spline inner/outer shafts and never had any more problems despite continuing to do extreme level trails like that.

But it's your $$$, do whatever you want. We can only advise and offer recommendations here. Most of us make such recommendations based on our personal experience.

 

[SvtLdr]

I'm with Jerry on this one. I don't understand your axle choice in light of your intended goals. PR44 and Dana 60 for a rig built for "long cross country trips, with occasional moderate wheeling."

Stick with the stock axles and save that money for fuel!

 

[The06LJ]

First of all, Thank you for the wisdom here.

So i can get away with just upgraded shafts, 4.88s and a locker? any brand shafts you'd recommend in particular? do i need to truss it, or add gussets or anything? I'd like to be able to take it to Moab next year and wheel without worry. In your opinion, will i need to upgrade the shafts in the rear axle when i do the gears and locker, or will that be strong enough for now?

I gotta say, this idea is very appealing, as it does shave several thousand dollars off the price tag, just seems a touch scary as i feel like I've been hearing stories for 20+ years of guys throwing good money after bad keeping their D30s alive.

 

[SvtLdr]

Yes, upgraded shafts are recommended when you add the lockers. I prefer the shafts from Revolution Gear & Axle. They'll be 4340 for both of your axles. No need to truss or gusset if you're not preparing for severe rock crawl duty. You can have a ton of fun in Moab on mostly stock equipment - just stay outta Pritchett Canyon. lol

I'd recommend going with 4340 chromoly shafts on both ends if you're adding the E-lockers as mentioned. See Jerry's note above on that. The front Dana 30 will be fine if you follow this advice.

 

[Jerry Bransford]

Yes upgraded front shafts are all you need. 4340 27 spline front shafts like from Revolution Gear or Yukon. Revolution Gear would be my #1 choice. No need for trussing, gussets, sleeving, etc. My front axle has none of that and it does trails that would scare 99.9% of Wrangler owners.

From your description of what you will be doing, the factory carbon steel 30 spline Dana 44 shafts in the rear will be fine. If you want to upgrade because you just want to, Revolution Gear's 30 spline 4340 shafts would be a good choice.

And if you saw the trails first hand that my previous TJ's Dana 30 survived with aplomb after upgrading just its axle shafts you'd quickly relax about the whole thing.

These are all with a Dana 30 and Dana 44.

 

[L J]

So i can get away with just upgraded shafts, 4.88s and a locker? any brand shafts you'd recommend in particular?

Yes. 4.88s are the numerically lowest I'd go. As far as axles go, I prefer the Revolution 4340 shafts with the larger u-joint but any 4340 shaft from a reputable brand should do.

do i need to truss it, or add gussets or anything?

no

In your opinion, will i need to upgrade the shafts in the rear axle when i do the gears and locker, or will that be strong enough for now?

Need to? Probably not but if you're saving thousands by not buying a Dynatrac 44 what's ~$600 on some 4140 shafts?

 

[Apparition]

I know that's not a huge difference, but in the multi-thousand mile trips I'm looking at in the next couple of years, that sounds like it might not be worth it, especially when I'm used to 3.73s now.

I've done the multi thousand mile trips in my LJ to wheel and return home. My recommendation is to start thinking of using your money on a tow vehicle because as you build you'll want to challenge yourself more and more and something may give.

I'm way more comfortable when wheeling when I know all I have to do is make it to the trailer instead of across country.

I've towed my jeep about 7500 miles this year to both the Rubicon and Moab.

 

[The06LJ]

Ok, Well you all have successfully convinced me not to set some money on fire. I'll just build what i have. Should i still replace my unit bearings, or is this more of a "if it aint broke, dont fix it" type situation? also, i guess seems 4.88's are the way to go.

As for the tow rig idea, it certainly is appealing, but ive tried things like that before, and decided its not for me. Instead i make the jeep more comfortable.

 

[Apparition]

Ok, Well you all have successfully convinced me not to set some money on fire. I'll just build what i have. Should i still replace my unit bearings, or is this more of a "if it aint broke, dont fix it" type situation? also, i guess seems 4.88's are the way to go.

As for the tow rig idea, it certainly is appealing, but ive tried things like that before, and decided its not for me. Instead i make the jeep more comfortable.

Factory seats suck so consider doing something there.

 

[The06LJ]

Factory seats suck so consider doing something there.

No doubt. My Interior guy thinks he can refoam them and make them more comfortable by making the seating area a little larger.

From what I've seen, the other options are Tiburon seats, which i don't like, or from another Jeep from the turn of the century, YJ, XJ and older TJ seats seem no better than what i have, and ZJ seats are a possibility. But WJ seats are the best option from what i can tell, but I'm not sure about the look of them in the LJ. Or maybe i've gotta look into having something custom made? i dont know, that's a rabbit hole i haven't gone down yet.

So who knows, you might find a lightly used pair of TJ seats with fresh foam and leather in a year or so.

 

[Jerry Bransford]

There are lots of choices of aftermarket seats made for Wranglers, my seats were made 40 miles north of me by PRP here in California.

 

[Jerry Bransford]

Ok, Well you all have successfully convinced me not to set some money on fire. I'll just build what i have. Should i still replace my unit bearings, or is this more of a "if it aint broke, dont fix it" type situation? also, i guess seems 4.88's are the way to go.

As for the tow rig idea, it certainly is appealing, but ive tried things like that before, and decided its not for me. Instead i make the jeep more comfortable.

Your existing unit bearing hubs should be fine, I wouldn't worry about them.

 

[Claybirdd]

Just to throw my .02 in, I too am running 35's and 4.56 gears the PO installed. Trust me it sucks going up hills and wheeling. At least get 4.88 gears. When I drop my super 35 in I'm going deep and putting 5.13 in.

 

[Just Chillin]

Ok, Well you all have successfully convinced me not to set some money on fire. I'll just build what i have. Should i still replace my unit bearings, or is this more of a "if it aint broke, dont fix it" type situation? also, i guess seems 4.88's are the way to go.

However, a set of new Dana/Spicer ball joints should go in when you have it apart (unless recently changed).

 

[NashvilleTJ]

One more thought driven by your post above, OP. If you are really planning on a power upgrade that will legitimately necessitate going to a Dana 60 in the rear (that would have to be a lot of power, by the way), a low-pinion Dana 44 in the front will not be enough anyway. So, staying with the 30 in front for now is a better choice - rather than swapping to a 44 now, and swapping again to cover your increased power.

The advice above is solid, and you will be in good shape for what you do.

 

[The06LJ]

It's been like 15 years since I actually used the forums. The last forum I used was apparently nuked, and gone forever. But I was about to spend 5 digits and I figured I should probably do a little due diligence. Now I'm really glad I decided to get a 2nd opinion before i just threw money at the problem.

I should also ask, what's the deal with RCV axles?

 

[AndyG]

The front axle seldom sees more than about 50% of the load the rear axle sees on a regular basis. For that reason and when running 35's, there is absolutely (!) no need to replace your front Dana 30 with a Dana 44. Simply replace its carbon steel 27 spline axle shafts, both inners and outer stub shafts, with 4340 chromolly axle shafts. With those shafts your front axle will be more than up to 35's, a locker, and doing the toughest trails your Unlimited is capable of doing. Really.

4.56 will not be enough gear for 35's, really, you need to go 4.88. Refuse to be talked into 4.56 by the sales guys at your local 4x4 shop who usually drive big trucks with V8 engines.

For your tires rubbing you can add a washer or two under each of the two steering stop bolts screwed into the knuckles. That will not restrict your turning radius enough to notice, it will still turn on a dime. I never bothered removing mine after getting wheels with reduced backspacing that would have stopped mine from rubbing.

This post will help you.

It may even help solve world hunger.

It helped me and I don’t even have a Dana 30 or 35” tires. I just feel better.