5th gear vibration

I wnated to know if anyone else who has an S60 R has experienced vibration in 5th gear and the 6-speed? I have in my car and the dealer told it was "problem" with 2004 S60 R 6-speeds. He also said they had a fix for it, which they performed and it did not work. Does anyone know of this and how I can fix it?

Thanks