rear diff moove in bulkhead ???????

I had a nitro revo for 2 years before, and nothing have probles with this , but now, i've buy a used revo (a piece of scrap) and order for $300 of new parts, including frame, bulkhead, aluminium diff cup, pushrod and turnbukkles, and convert it to electric.

But this rear diff make me sleep at 2:00AM for past three nights.

I think i'll run it like that and see what appen