The JK30 uses a carrier with a slightly wider internal dimension vs the TJ/YJ D30. Where the OEM spider gears sits is ~0.040" narrower on a TJ. This means if you put a "TJ" lunchbox locker inside it, it will likely not operate properly as it will have too much lateral movement. You can run a TJ D30 carrier inside the JK30 as the outer/critical dimensions are the same.
However, for the sake of simplicity and your needs, the Aussie Locker is a good option and they make a LL specifically for the JK30:
https://eastcoastgearsupply.com/i-1...UEyuV2mP00vjrf_DJHubKvevR7LU-iLpA75IKWJkD-Urq
Whether or not you need to worry about axle strength is dependent on many factors:
- Does "when in doubt, throttle out" mean anything to you?
- Are you okay taking bypasses when your friends are hitting the hard lines?
- Are you comfortable carrying spare parts and doing trailside repairs?
- Are 35"s the absolute biggest tire you plan on running?
- Are you regeared properly already?
A decently built TJ30 will hold up near indefinitely on 35"s if maintained and setup properly. On a 2-door JK, they are practically indestructible as well. When you step into the 4-door JKU world, the JK30 holds up moderately well, though due to the inherent weight and width differences, they do experience more long-term fatigue failures. Issues like bent tubes and inner C's are much more common on JKUs (but are nearly non-existent on TJs), regardless of trail ratings. I've seen a number of bent JK30 housings in JKUs that have seen nothing more than dirt roads and pavement.
The issue of strength and longevity is exacerbated by increasing weight. If you plan on hitting 8+ rated trails with confidence and enjoyment, you'll likely be adding a considerable amount of weight in armor, skids, and more. Suddenly your ~4200 lb. Willys is now pushing 2.5 tons. Throw in a passenger, spare parts, extra fuel, a larger tire carrier, bumpers, winch, beadlocks, etc., and your Trail Burrito has now eclipsed 5500 lbs. in many cases.
It's at this point where breakages are common and frequent. It's also where they become spectacular and catastrophic...
It should be noted that the JK44
also suffers from weight-induced failures, since they essentially have the same housing strength:
Seeing stuff like this is not uncommon on the trails out west:
https://jpfreek.com/2016/01/06/broken-axle-housing-lessons/. Nena (from Barlow Jeep Adventures in Sedona) used to have a bunch of photos on one of the local AZ Jeep Facebook pages of all the destroyed axle housings, but I can't find it now through a Google search.
I know somewhere in the future there will be some dude (b/c it's always a dude!) reading this and going "man, I wheel my JKU on a D30 with 42" stickies and I have never broken anything while driving KOH style all over Johnson Valley". Sure you did bruh, sure you did... The truth is that many people overestimate just how hard they're running, and just how hard the trails they're driving on are. Many are also running tires that are larger than necessary, which helps eliminate some of the challenges and allows them to take lines in an easier way.
Will you be able to make one last? Possibly... you may have more issues with an LSD in the rear than a LL in the front, but that's a topic of another discussion.
On 8+ trails, 35"s are basically the MINIMUM, as is a winch, skids, and more. You'll be able to do most of the hard lines, but they will require finesse, skill, patience, and in many instances, having someone run a winch line. There's nothing wrong with this - it's actually what makes wheeling fun. I'm in my 40's now, so I overbuild b/c my a$$ and back can't stand 4-hour trailside repairs like they did when I was 19 lol. That said, if you're wheeling with kids, prefer not to do repairs, or are otherwise worried about ancillary damage (i.e. smashing your roof/cab because your axle broke and you slid into a canyon wall), then you may want to take a long, honest thinking-session about what you're comfortable with and go from there
