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 had to address outter wheel hub seal issues on my 2014 RAM 2500. When I did that work I also bought an AAM aluminum finned diff cover. It has the same internal volume as the stamped steel cover, but gives you the cooling action of the fins. I haven't taken temps on mine but other reports I've seen show significant decreases with the aluminum cover.
