Ok we just put a plow on it and I noticed that it would clunk really bad ever so often almost as it feels like its jumping out of gear or out of 4x4. What could this be and what could be done? Its my cousins truck and he brought it up to some guy just now and hes saying something with the slipyoke or whatever and the pumpkins and transfer case fluid should be changed. All for 500.00 LOL! No thanks buddy.