?71 3/4 ton 4x4 front end not working corretly making loud popping noise and slipping

[Brewski*]

My 71 3/4 ton 4x4 front end is not working correctly. I was up cutting wood the other day (ice and snow) and backed up a small hill. Heard a loud pop (passanger side) now it kinda does this slipping> pop> engaging slipping> pop> engaging. It will drive for a while then do it again when I stop and start. Seems to pull to one side a little and steer funny when not working. I already changed out the Warn locker on the passanger side it did not help. Checked the locker on the drivers side it seems fine. Any clues? HELP?