It done it when I first got the car but the vent tube in the housing was loose so I repaired it and after a long trip its doing it again,I thought the pinion seal went bad but the hose from the vent goes up in the frame and it was dripping down near the yoke. I checked the lube and it was almost full but what could cause the lube to heat up that much to blow out the vent unless I over filled it. Jeff