Audi Q5 2.0 tdi weird ticking sound when stopped

Hello, I recently bought a 2010 Audi Q5 2.0 TDI automatic (Tiptronic transmission). I didn’t have much experience driving automatics before, and now I’ve noticed that when I come to a complete stop at a traffic light or stop sign, I feel slight vibrations through the steering wheel. The engine is at around 900–1000 RPM at that moment.

These vibrations also seem to transfer to the air vent on the left side, which produces a strange noise. When I shift the car into neutral, the vibrations disappear.

The transmission was fully rebuilt about 30,000 km ago.

Is this something to worry about, and if so, how serious could the problem be?