Transfer Case probably has a Hole in it,and lost most of the fluid.. When I bought mine it had a small bump, which then got alittle worse... I took it to a tranny shop and they said they were unsure of the problem.. Even had my mechanic buddy look at it with nothing.. I finally got under it and started looking, Pulled the plug on the transfer case and very little fluid came out.. I filled it with 2 quarts or so,and the next day I had it sprayed all under the truck.. I heard to do the pump rub kit,or you can fix it with water weld.. I sanded and put water weld on it,and its still been holding..