When I bought the jeep I was aware of a orblem but i have yet to be able to figure out whats wrong. When I let off the gas pedal while driving I hear a clunk about 70% of the time and very rarely it when shifting into reverse it makes a grinding noise(a prety loud one at that. Please help

 

U-Joint. Start there.

 

Ok. I can do that. I was told it could be the t-case by the kast owner but i highly doubted that. I guess its not a good idea to take it out today then?