Start checking things like front and rear shafts, look for rust coming from the joint caps, looseness or overly tight conditions, check the front shaft at the t-case and see if the centering flange yoke is dry or has any looseness or non free moving cycle, any squeaks.
Other than that from what you described it's about where i would start looking otherwise anything else is all a guess
1995 Jeep gc ltd, 2005 Jeep gc ltd , 71 Dart, 73 RR 440-6pk, 85 Power Ram W-350, 92 Daytona, 99 Dakota, 08 Ram 2500
Less than 8 is like playing with half a deck
Long Island Motorsports Association