850 TDI, automatic – Strong vibrations in idle mode

My TDI (automatic) has been having annoying vibrations for quite some time in idle. This only occurs if I stand at the traffic light in stage D. Switch on N or give me only a little bit of gas, it is immediately gone. My guess was the two lower and the right engine bearings, which after 390,000 km could adjust their function. However, according to the workshop they are still in order. Now there should be a bearing next to the automatic transmission, which should lie sideways. That could be the cause. Someone knows this bearing and can tell me the position. In principle it would also be enough if I slightly increase the idle speed, but this is not possible. Greeting Holger