Many off road racers and others who work their off road trucks use "catch cans" on their diff and transfer case breathers. They are actually small expansion cans very similar to the ones used on radiators, with a fitting inlet connected to a tube that reaches to within a fraction of an inch of the bottom of the can, and a filtered vent fitting on the top of the can. Any oil that gets caught in the can and reaches above the level of the bottom of the tube gets pulled back into the diff as the cooling draws air back in through the filtered vent. However, in your situation, one or another of the fixes already put forth should work quite nicely; my suggestion is just another bit of fodder to toss in the idea mixer.