I've got a 2003 c5 A4 and it has developed a knocking noise coming from under the car. you can hear it the loudest at idle when the car is warmed up. I've lifted the car up and it sounds like it is coming from the bellhousing area but I could not find any damage to the flywheel looking through the little inspection hole on the bellhousing. My guess is the torque tube has gone bad but I'm not sure. If anyone can point me in the right direction that would be greatly appreciated.

 

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