Shaking clutch and clattering engine

subaru
engines
outback
clutches

#1

On one hot sunny day, I drove down to JFK from Worcester, MA and just as we got to the parking lot the engine started to make a clattering noise as if while something was spinning it was hitting a metallic object. Not only was the engine making that noise but the clutch started shaking. It would go away one I reved the engine. I had the car looked at by my dealer but they said everything was fine. So I believed them and continued to use my car only till yesterday the same thing happened. The clutch disk was replaced last winter. I’ve had all my fluids checked and filled every 3000 miles. I also tend to drive the car in high revs. What might be the issue?