My dad has an 89 dodge 4wd 150 and has had it since new. It has always clunked. He has used it to plow snow since the day he bought it. It hasnt broken a single thing in the drivetrain and he is rough as hell on it and it doesnt see much maintanance at all, shes about to roll over 180,000 miles.....the clunk is there to stay and its not a reason for major concern, considering he does part throttle rev to forward shifts in plowing....it will be just fine. dont get rid of her because of the "dodge clunk"