It was not a fun discovery being that I could swear it was coming from the rear diff.... was just doing a routine oil change. For the front since I was cleaning up the rear anyways. Turned my day into a not so happy one.
We pulled the locker out last night and pulled it all apart. These early design ARB'S rely on 6 tiny 6mm bolts to hold the locker together. There are also 3 pins that hold the cross shafts together. Those pins also come out when those 6 bolts break and fall out. Then, the 3 cross pins start to slide out and bounce against the ring gear. I can't believe there wasn't any damage to the R&P. The cross pins got pretty hammered though.