If both sides began leaking at the same time, I'd suspect the axle was overfilled. AAM (the axle manufacturer) revised the fill level. It should be 3/4" BELOW the fill hole, NOT the traditional AT the fill hole level. I think the lube difference is less than a quart, so it isn't much. Their reason for the revision, as I recall, was that an overfull may cause the inner axle seals to leak.

That said, it is likely your seals aren't failed. What happens, due to an overfill, is normal thermal expansion causes the higher fluid level to obstruct the vent, and create a positive pressure condition in the axle, which forces the lube to pass the axle seals.

As well, if you're seeing a fluid leak, the E-brake shoes are likely contaminated with axle lube. If it hasn't been for long, you can simply clean the lube from the shoes, inner drum (inside the rotor, AKA: Drum-in-Hat), and area with brake cleaner. Most often, the E-brake returns to normal function. If the shoes are saturated and the lube has penetrated the friction material, they should be replaced.