In my mind, when the engine and gearbox is hot, if its oil related, the viscosity of the oil being thinner would let moving parts move/rattle more freely. If its moving parts warming up, then it could be rubbers etc. Audi were useless. Especially when asked " when the transmission is engaged in D or R, what happens to the rest if the car, solenoids, actuators moving etc etc", I got a blank look 😅. What happened to mechanics actually knowing how things works 👀😅. To answer the swirl flaps, those codes always show up as per previous experience in my older A6 I had. They are good. As for the prop shafts and drive shafts, could you please elaborate on your train of thought. I really appreciate your assistance. Thanks.