Bought a 4420 about a month ago. seems like a dicent combine we paid 6800 for it with a 4400 parts combine. The motor went out of the 4420 so we switched it for the one in the 4400. Ihe 4420 has around 3000 hours on it. The guy before me put all new clean grain augers in it along with some bearing and all new belts. the only problem I have had with it is the variable speed on the feeder house. The plats that rides on the fork broke about 50' into a corn field and the belt started slipping also the belt drive slips a lot when I have a full bin so I need to adjust that. what I would like to know is whats good about this combine and what do I need to watch for?