I'm having the same issue. Started around 5000 miles and has gotten worse. At 30K now. Took it back to the one dealer twice. There recommendation was to keep driving it till it breaks?? Went to another dealership recently and changed the fluid and reset the learn process. It made no change, I've got another appointment in a couple weeks.
My vibration is most noticeable when the driveline is "floating" not pulling or holding back. As soon as you take the slack out of the driveline it is smooth. It does it at all speeds but it is more noticeable in 40-60 MPH range. Especially on flat to slightly down hill roads
