got a 2004 6MT G35...close to 65K on it...now hearing a chatter comming from the manual transmission but only when agressively acelerating..and it wont start making noise until reaching about 4,500rpm...if I come off the gas and just accelerate normally..theres no sound until reaching 6k rpms...have any clues? I hope its not the clutch again, had to replace it at 30k miles