This manual contains information concerning the adjustment and maintenance of the John Deere 6620 , SideHill 6620 , 7720, and 8820 Combines. Please have all operators read this manual carefully and keep it available for ready reference. With this in-depth & highly detailed manual you will be able to operate on your vehicle with the absolute best resources available, which will not only save you money in repair bills but will also help you to look after your business.