Vibrations
 

A4 B6 ALT Engine CGS Gearbox. When idling but not in gear car does not vibrate. When idling and in drive car vibrates. I cannot determine whether engine mounts need replacing or whether gearbox mounts ( I am assuming they have mounts too!) need replacing. Any one else had this problem and if so how did they resolve it?

Are the RPMs holding when you place the transmission in gear, or is the engine slowing down? If the ECM fails to maintain idle speed then the engine will naturally idle rough, regardless of engine mount condition.

The revs are constant. I even checked the engine parameters with my VCDS and all appears to be well with the engine..........at least.