Knocking from rear diff/prop/drive-shafts

[GreenLaner]

Since having the rear subframe replaced (not by Mercedes) I've had a knocking sound coming from the rear somewhere. It seems to be prop/diff related as it occurs at the point you go on/off throttle. However, there is no play in the prop or donut. There is, however, noise coming from the two drive-shafts, specifically at the point they 'attach' to the diff. Tried to make a couple of videos (below), but not much room under the car for clarity and light. Should they move in/out like this?

Video 1

Video 2

Thanks,

Scott

 

[toteimerced]

Looks like the snap rings, were either not replaced, or not fitted at all.