it was running great and still is except when i am stopped i start to hear this rattling, i can even fell it under the car. i think it might be the tranny but im not sure is there anything else that could be causing that noise. its loud and you can feel it a lot in reverse, same in drive but usually not as bad, and really quiet in neutral, help me please i need to figure it out before the warranty on my tranny runs out

 

A4 or M6?

I had a loud rattle under my car... damn heat shield on one of the cats came loose.

Best thing to do is with it rattling, reach under the car with a pry bar and start pushing/pulling on stuff and see if the rattle goes away. If it does, that's good because that means the rattle isn't internal to the tranny