Rusty frame. Just had my junk fixed two weeks ago!!
I have modified rear shock mounts in the rear of my Jeep, and the drivers side was rusted thru at the frame, which took out my upper shock mount, and had about a 4" crack on my passenger side frame underneath in the back, and was loosing metal on the drivers side in the same area.
I took it to an Off Road Shop that has done this repair many times. They did a kick *** job on the repairs. The rest of my Jeep will fall apart, before these welds will.
Just try to find a good shop to do the repair, and you should be good to go, unless your frame is beyond repair.