You can usually get a good idea of anything serious being wrong by draining and examining the transfer box oil (I had square roller bearings falling out of one of mine).
A fair bit of rotational play is pretty common though, any axial or...
We could do all sorts of guessing, but it would help to know whether they moved the engine or the gearboxes.
Either way though, best bet is to take it back and let them sort it.