Shuddering Motorhome at shifts
I agree on the no code but bad coil pack on the plug issue. I had 3 that were bad on my 2005 V10 on my prior RV. I could replicate the problem while under load on certain hills and at lower RPMs before it downshifted. There are also issues that can happen with the boots on the plug itself.
I realize that your rig is quite new, but there still could be a defect on one or more of these. Don't let Ford weasel out of fixing it, especially while it is free under warranty. If the tech is too lazy to take it out for a road test under load (any hills nearby), find a different dealer. Plugging in an OBD reader and saying "nope, no trouble codes" isn't sufficient. Also, saying it is underpowered is also an indication that they don't have a clue. He's just hoping you will go away.
History: '08 View, '05 Chinook, '01 Jamboree 24D, '78 Apache Popup, 81 Komfort Tlr,
84 Mazda B2000 'w canopy,
Tent from wedding shower in '96