my car had the same problem also but i didn't think about it to much. today i swaped my tranny out caus it finally blew (145,000) miles and had to take drive shaft out so while i was at it i canged out the yolk on the diff and the fluid. it isn't making that noise ne more. so try changing the diff fluid and if that dosn't work u can get a new yolk right from nissan
