1996 Redneck F150

my truck clunks in the front end to.... i dont even have to actually ENGAGE it in 4x4, i can just lock the hubs in and it clunks.... it popped real loud one day when i was backing up out of my steep yard ( i was in 4LO).... it popped so loud that it sounded like a gun shot went off.... i looked down, and had the park brake set, so yea, stupid move on my part.... i still haven't found out what i broke.... u-joints are good, no broken axles....my local garage SWEARS its the transfer case.... i locked it in 4x4 the other day and the 4x4 driveshaft has more slack (back and forth) than the rear does.... so im thinking i fubared my dana 44 front end up.... more than likely the ring and pinion gear (thats what im thinking)....any other ideas?