SDrive35 Engine Smoothness

[JLR_X5]

New here. My 2014 with 8,500 miles in the shop for a vibration. Anyone experience the following?

-Roughness through the throttle pedal and footrest when accelerating moderately and the trans shifts up and revs drop to 1,400-1,500?

--More obvious when you accelerate a little harder to merge into traffic, then as you ease off the throttle and the trans shifts into 4,5, or 6 there is a buzz or rumble sensation around the feet.

--Eco Pro makes is worse because of the lower revs and lugging engine.

--It disappears at highway speeds or above 2,000 RPM.

--There are no unusual sounds and it is not dependent on vehicle speed. it almost seems like an exhaust or heat shield vibration. Perhaps trans mounts.

I am hoping the dealership can diagnose, although they just backed the car into a wall so I am a little skeptical of their abilities.

Any help or insights would be appreciated.