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
Groover wrote:
I find it interesting that the entire discussion so far is concerned with keeping the differential cool but Ram recently added a differential warmer on some trucks. Overheating is bad but so is overcooling. Finding the sweet spot for your application is the trick.
I think they added the rear diff heater for mpg reasons for times when the very viscous gear oil is cold - not sure where you're from but where I'm from, 80w90 gear oil is like a bar of soap at -40 and will rob mpg until it reaches operating temp. When we see the data from Banks on the running temps of gear oil, I suspect it will be higher than running temp of the coolant, or maybe RAM has a way of turning the coolant flow to the rear diff on and off depending on temperature.
