My 80 was making a loud clunk noise from the driver side wheel during sharper turns and this morning when I went into reverse the same wheel locked up. I parked uphill and went into neutral and when I rolled back, same thing. The wheel would lock up, then you could hear it pop, then roll back (then it kept repeating this). I ruled out any tranny issues because it happens in N and R, and wanted to see if anyone has advise before I rebuild the diff. Any advise is appreciated.