This stock Explorer/Mountaineer 8.8" IRS cover is an upgrade from the stock stamped cover, which is prone to puncture & leaks when wheeled in the rocks. The large ears don't extend behind the normal cover, or above the axle tube, so clearance isn't an issue. The only mod was threading the vent port for a 1/4" MPT-5/16" hose nipple adapter (not shown) which is where I attached the extended vent line, and through which I can fill the diff from the RHR wheelwell.
This is a 1L2Z4033AC (2002-06), but 7L2Z4033B (2007-10) will probably work just as well.