904 5 Clutch drum swap

Unfortunately you need a new pump support designed for a 5 clutch drum. You’ll notice the foreward side of the drum is tapered and the pump support you have is not tapered to accept the drum.

This is why folks put 5 thin clutches and steels in a 4 clutch drum. Or use thick ones and shave down the piston or the the other side of the stack (I don’t recall it’s nomenclature)