Analysis of Leakage
WARNING: This page is about a different car, the 2007 Lincoln Mark LT and 2007 Ford Pickup. However, it is still accessible from the selected car via links, so may be relevant.
Clean the leaking area enough to identify the exact source.
A plugged axle housing vent can cause excessive pinion seal lip wear due to internal pressure buildup.
Verify the lubricant level is at least 3-5 mm (1/8-3/16 in) below the bottom of the fill hole.