Differential covers 101
PU Truck mag That answered a lot of my questions about these covers. Extra large ones may not make a lot of sense because they disturb the oil flow in the housing.
Forum Discussion
I never considered the fluid flow, but it makes sense. The upgraded Dodge cover is pretty much the same inside as the regular steel one, so fluid flow should be similar; however, it's aluminum & finned for better heat dissipation.
