I have a 1688 and I was thrashing corn today and started to hear a noise. Pretty high in frequency. I was checking all the pulleys and found that the main machine drive pulley was somewhat easy to move with a bar. I have about 60 hours of thrashing for the season and wonder how long it would run that way. Does that shaft go through the clutches into the main pto case or is it short. Any info would be greatly appreciated.