I noticed this while underneath the car. At first I thought the noise was coming from the engine. Now I realize that the niose is coming from the bell housing. Like a knocking or tapping noise. Took the stethescope to the bell housing and you can hear it. You can't here it though the engine. The noise does not change with the clutch in or out. The noise goes away with RPM. THe noise is not always there. Any ideas?