Diff oil out the vent, why?

Dana67Dart said
Is the vent on the side of the hump or on the axle tube?

Is the vent new or old

If not too full, a fix would be to weld on a splash cover inside the housing like valve covers have.

The vent is on the side of the hump, it is an old vent. If I end up taking it apart, the baffle idea sounds good. Thanks