We are having trouble with the variable drive belt breaking(some times more than once a day) on our combine and this morning it took the cylinder belt with it. We have changed the cylinder bearings, primary counter shaft and bearings,the sheaves on both ends of the belt have been gone through. Has anyone any idea of what else to look for. This evening the belt flipped inside out and jumped out of the bottom sheave, and sliced the belt. The pulleys are running in-line.