For those interested (and for those that didnt believe in a SWM failure) - the lens AF problem re-appeared again recently on the 400mm on a sports shooting. Its driving me nuts. I did send it back to Nikon but they do not seem to have a clue whats going on. Next is mount change and contact block change. But I do not believe that this will solve the problem ... AF squeeking sound however disappeared after repair - maybe indeed time for a new lens. Best! Sören
