Thanks guys. It isn't my Propeller nut. I checked that and it is tight with cotter pin intact. You can hear it coming from the Hurth Tranny. Sounds like rocks like Todd said. I'm going to have my dealer change it out to enginge oil. It needs to be changed anyway. Only reason I'm having them do it is so they can also listen to it to make sure it isn't the damper plate.
Sorry B-Rad, I would and could probably do it myself and normally agree with you, but I just don't have the time to spend on it! Too many other projects going on, working full time and running a small business on the side!