what control arms where put on? Sounds like you have bushings going bad. I would check all bushings, Make sure your tires are not over inflated as BLACKJKU said and post up some pics, that will up us see whats going on.
I do the same, bead locks, plugs, patch kit, onboard air and full size spare in the cab...as soon as I take out one, I'll need it on the trail, or atleast I think i will.
We just did 5.13 in the wifes JKU, we had 4.10, huge differnece. The place we went had a REM polish (i think its wahts its called) they ran the new gears thu a machine so we didnt have to deal w/ the break in period. This is the 4th Jeep i have had re-geard, lack of a break in period and lube...
Looks to be a Jonnhy Joint, you can rebuild the joint itself, or buy the whole arms as suggested. I would rebuild.
https://www.rockjock4x4.com/search?show=48&keywords=johnny%20joint
It has a 600 lb load limit. The part w/ the ladder has a locking mechinism that hooks up to the other side. Im 240 and it didnt seem weak to me when i was up there.