Welcome to the board!

Having never heard anything good about the D35, I wouldn't invest as much as a new pinion bearing in one. Explorer 8.8s are too common, tough and easy to swap.

I've heard plenty of good about the front D30 for moderate wheeling. Several guys on the board have flogged them pretty hard without adverse effect. On the other hand I shucked teeth off the ring gear backing up hill out of a muddy ditch with worn-out 31" MTs, so would personally never invest significant money in one. For about $250 and a weekend's work I replaced it with a D44 which will almost certainly not break, and got better brakes in the bargain.

As for the locker choice, if you can afford only one selectable locker, put it in front. If you can afford two, great. When I get around to lockers I'm going to look seriously at the Eaton E-locker and Detroit Electrac. Switching directly with electricity seems more attractive than using electricity to control valves to control compressed air from an electrically driven compressor.

 

Idiot, check your PM's.

 

Idiot, check your PM's.

That's MISTER Idiot to you!

 

I don't think that you are going to find too many people who are going to say that the stock axles in your jeep are good for much of anything over stock size tires. A lot of people run the stock set up with 33" tires and if you are carefull you can make them live. The front Dana 30 is stronger than the rear, you can usally make them live with 35's.
However... if you throw lockers in them.... all bets are off. The question is not if they will break, more it is when will you break them. You will be way ahead of the game if you find a set of D44's or an 8.8 and a 44.

I remember back a few years ago... well maybe more than a few. I was pretty new to my jeep, I had it for 2 years stock-ish. I told myself I would never go bigger than 33's so I got a SUA 4" kit and had a great time for a few mroe years...
Now, my jeep has a 350 in it, a SM465, D300, ARB's front, rear, 4.1:1 RP and is on a pair of D44's that I have quite a bit of work and $ into. I told myself I would never have bigger than 36's...
Well, now I have a set of 37's and I love them but I do have to be careful to keep my axles alive and I do have to keep an eye on them. I wish that when I did my rebuild I had gone with a D60, and a 14B....

I would look for a set of new axles if I were you, jeeps have a way of growing bigger while your bank account grows smaller....

 

Do yourself a favor now, Learn from others mistakes. Jim said he wouldn't waste money on a Pinion bearing on the D35, I wouldn't waste money on crappy RTV to seal the diff cover personally.

So many have been in your position before. some listen to others, most ignore and regret it later.

Gear and lock the 30 and run it. You'll be fine on 33's and moderate wheeling. NOT INVINSIBLE, but your biggest concern will be Unit Bearings more than likely.

Find an 8.8 or 44 to replace the rear axle, and build it. May seem costly now, but cheaper than dumping money in the 35 and then building an 8.8 or 44 after you learn the error of your ways.

I've heard people say I love my 44, or I love my 8.8, or my 60.... I'm willing to bet that no one has ever said (seriously) I love my D35. Loath yes, love no.

 

I'll throw my vote to 2 1/2 ton Rockwells, Unimog or Volvo Portals. Hey, if'n you're going to throw money at the problem.. throw some serious cash at it!