Van vibrates when engine under load

Recently there has been quite a severe shake in the van when engine is under load in 4th,5th and 6th gears. it may also happen in other gears but I haven't noticed it. It feels like a wheel out of balance , and thats what I orginally thought it was, but this trip I've noticed that it's not happening at a certain speed, but is more linked with lower revs and acceleration through gears when I'm going up hills and the engine requires more throttle, or dropping gears. The van is a 2018 2.3 150 hp Ducato. Has anyone else had this issue?

It's the driveshaft bearings. I had it on a Nissan inter star. First I got the tracking and wheels balanced that did not fix it. Took it to the garage and was told it was drive shaft bearing.

Besides the propshaft carrier bearing, have a good look at the engine and gearbox mounts, also all the exhaust brackets, rubbers and heat shields in case it is hitting the under body when the engine shifts with the torque effect.

Brilliant, thanks. I will have them checked.