You should get some grease into the box, John Deere corn head grease is the closest to the original spec for the box. It sounds like the box needs to be adjusted. If you look in the service manual it explains the steps to do it. You will need a pull type fish scale to do it and they can be had at Wal Mart - K Mart type stores. Make sure that you have the box in the center of its travel when you start your adjustments. When the box is on center its at its tightest point.
