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
If finned aluminium covers weren't needed or didn't have a benefit, the OEMs wouldn't go to the expense of adding them. It's a fact that aluminium dissipates heat better than steel. Any adult knows that. It's also a fact that adding surface area (fins) to anything that is hot will make it reject heat faster with the same BTU input. It should be plainly evident that a finned aluminium cover of the same, size, and shape as a stamped steel one, even with the same volume of gear oil will run cooler. How anyone can debate that is beyond me.
Now, as far as it being necessary, only the OEMs or axle manufacturers know that. I'll trust that they employ engineers that know what they are doing and that they design an axle assembly that can stand to run at max GCWR/GAWR, uphill, in extremely hot temps and survive.
Some may say they have xxx,xxx miles on their rear diff without a finned aluminium cover and never had an issue, that's great. But remember the OEMs have to design for worst case scenario that you may never experience.
Kind of the same concept as a diesel tuner. The OEMs need to design an engine calibration that will work just fine in Alaska at -45* and Death Valley at 120*.
Now, as far as it being necessary, only the OEMs or axle manufacturers know that. I'll trust that they employ engineers that know what they are doing and that they design an axle assembly that can stand to run at max GCWR/GAWR, uphill, in extremely hot temps and survive.
Some may say they have xxx,xxx miles on their rear diff without a finned aluminium cover and never had an issue, that's great. But remember the OEMs have to design for worst case scenario that you may never experience.
Kind of the same concept as a diesel tuner. The OEMs need to design an engine calibration that will work just fine in Alaska at -45* and Death Valley at 120*.
