I guess I should say that the vibration is more related to car speed than engine speed. The vibration does not occur if sitting still and revving the engine up to 4K. It also does not occur while shifting through the lower gears at different engine speeds. It begins in high gear when I pass the 40 mph mark.
If I shift into N at 60 the vibration goes away. If I go back into D the vibration returns as long as the speed of the car is still over 40mph.