We are having the same problem on N5, if you follow the links on the left to the tips section you will see that the experts say this is a problem on the lift side of the valve. We did the same thing as you and got the same results. Still trying to work up the courage to tear into the other side and do what is recommended. looks like a real pain to do the inside one. Is there a way to take the valve stack down to work on itIJIJIJIJ. doing it mounted to the combine looks like a real patients killer lOl.