I have a 485 JD backhoe mounted on a 3520 JD tractor. Since day one the primary boom moves up and down as well as left and right just WAY TOO FAST. I put up with it for a long time assuming operator error but as time passes I'm growing tired of looking like a hurky jerky operator. The other controls for the secondary boom and dig bucket work as expected and can be feathered. Any thoughts or ideas on how to calm this thing down are very much appreciated.