I have a 2000 Honda Fourtrax. I recently aquired it from my father. A few months before I got it he had to get the frame rewelded in a couple of places becasue of numerous breaks. Since I had it I have noticed a knocking noise coming from what seems like the drivetrain. It comes and goes depending on types of terrain and it is also there on hard takeoffs. Someone mentioned that the drive shaft might be worn and slipping from where the frame was broke and my father used it a couple of times not knowing it was broke. Does this sound right or might it be something else?