engine niose

Whenever I start the car, after it shfts into third gear, there ia a clunk in the engine compartment. It never happens again until I re-start the car. Anyone else have this problem?
 
JIm

Every time I start my 2007 Azera, and after it shifts into third gear, I hear a "clunk" in the enine compartment. It never happens again unitl I re-start the engine, Anyone else have this problem?
 
thanks
 
Jim