Well i recently replace all the bad U-Joints in my truck i still hear a pretty bad thunk/grind coming from either the shaft or the transfer case. But its strange because its only at a slow crawl or tight turns it seems. Maybe the carrier bearing or whatever that is is bad? I dont know. and its making me mad cause i hate thunks they are just worrying. If anyone has any ideas itd be a real help. also when u crawl under there and gently twist the shaft with weight on it i hear what sounds like a chain josseling inside? is it supposed to do that? it doesnt sound broken. (I know to check u joints to jack it up) so yeah any ideas would be awesome thanks!!!