Clunking when in 4x4

Alright so i've searched a bit and found a topics similar to my problem but not exactly the same.I'm thinking it could be either the motor mount,tranny mount or my transfer case but i want to figure it out before i go out and buy another t-case since i found a decent deal and the sell wants to get rid of it soon.The symptoms/issues are when i put the jeep into 4x4,there's a clunking noise coming from the front/mid part of the jeep,and i can sort of feel something everytime i hear the noise. It's a 97 xj sport with a 3'' lift,and 31's.