Building an LJ - Auto - with 35's - front gear / axle options

KBOOM

Jeep Newb
I'm repairing and rebuilding an 04 LJ with auto transmission. I will be running 35's and 3.5 metal cloak short arm suspension. I'm looking to keep it LCG as is reasonable. From my research the appropriate gears for an LJ and 35's with an Auto are 5.13's to be able to use OverDrive effectively. The problem as everyone knows is the otherwise capable D30 doesn't have room for 5.13's. There's a company who now makes 5.13's for the D30 (tj and XJ) but i can't find much info on them. I have 4 options i'm looking at:
1. Keep the TJ D30 use 4.88 gears (of course i could also get the XJ D30 and run 4.88)
2. Keep the Tj D30 use 5.13 gears from Revolution
3. Buy an XJ D30 use reverse 5.13 gears from Revolution
4. Buy aftermarket G2 D44 (but i don't really want to spend the $3K+ and run 5.13's.

It'll be a Pacific Northwest crawler, not commuter rig but will see hwy miles (not trailered) for hunting / skiing trips so don't want to over gear. I plan on going either 4:1 rubi case or Atlas as well. Which would be the best option? Not trying to spend a ton of money before anything breaks but I don't want to buy multiple sets of gears / lockers. I am watching Craigslist for axles to see if any good options pop up.


Cheers,
Boom
 

Pthorpe84

Moderator
Staff member
Would you be open to getting Jk axles! Doesn't necessarily have to be rubicon's. But it's pretty easy to find JK D30's for little to nothing. Just a thought.

My question is what is the difference between a TJ d30 and a LJ d30? Isn't it still just a D30? I know there are plenty of d30 5:13 gears out there


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KBOOM

Jeep Newb
Tj/lj axles are the same but the lj is heavier so plays maybe into whether an axle is strong enough or not.

As far as I know the only 5.13 set for a tj or xj d30 is revolution? Tru a jk d30 will handle 5.13 but then would $600 truss / brackets from tnt or equivalent so maybe that's an option but drives up costs a lot.
 

Cloaked Willys

Jeep Fanatic
I would stay away from d30 5.13 gears due to how small the pinion becomes with that ratio. A HP30 will be a little better because the load is on the stronger side in the front that way. We are running 5.13 gears in out LJ with 37's and it works great. That LJ did start out as a non rubicon that got a G2 d44 front and 4.3:1 atlas. I would not spend the money putting a locker in the d30.

Doing the JK axles are not a bad idea and Artec does have a truss for the setup now.
 

Pthorpe84

Moderator
Staff member
Agreed with cloaked. Ring and pinion on a 30 is small. If you want to crawl....go get 44's. They will be great for your application. Not to mention the JK axles are wider and will give you a nicer stance.


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KBOOM

Jeep Newb
So you think if I swapped in a JK Dana 30 with arctec truss i could run 5.13's+locker? I can find those axles real cheap. Are they better than an XJ HP30? I already have a D44 in the rear so i don't want to swap that out. Would it be a problem having the wider JK-30 up front?

Cloaked, I like that setup, G2 D44 and an Atlas 4.3 if I did that the step to 37's is inevitable...

I'm adding a bunch of steel to my LJ with metal cloak fenders + bumpers so I'm worried i'm going to hate 4.88's.
 

Pthorpe84

Moderator
Staff member
The JK axles I think is wider than the 44's that came on the LJ/TJ platform. Either way it's still a D30 ring gear. You can run it, but it will still be weak at the ring. With 35's you will be ok as long as you do not get heavy on the gas pedal, but no way I would run 37's. Try to get front and rear Rubicon 44's for 4K or less and sell the 44 rear you have and put it towards 37's.


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lindel

Jeep Owner
The D30 in the TJ/LJ is up to 35s, with a decent set of Moly axle shafts and a full case locker. The 5.13s are a little dicey, for the reasons given above. 4.88 gears work well in the 30, but that ratio will be a little high, with the 4 speed.

If you want to run 37s, you'll need a beefier front axle, and I wouldn't trust the rear D44 all that much. If you were to add lockers to the mix, you'll be doing axle work soon after.
 

FC4X4

Jeep Owner
Ditch the 30 for sure. I think 5.13s are a good choice. That's what we run in our LJ on 35s.
 
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