Sorry the noise it hard to explain. Didnt you ever take a ruler or meterstick/yardstick and hold it on a table with your hand but leave most of it hang off the table, then hit the end hanging off the table so it is moving up and down...then pull it slowly onto the table while it is moving up and down? It is a very distinct sound. Try it...! It sounds like a little gremlin running around in my Z!!!!!