Abstract: An axle assembly having a differential gear set is provided. The axle assembly includes a housing cover having a first surface. A housing is provided having an interior portion sized to receive the differential gear set. The housing includes an end with a second surface, the second surface sized and shaped to engage the first surface. The end has an opening that extends from the second surface into the interior portion. The housing further includes a cavity formed in the second surface, the cavity defining a labyrinth passageway that fluidly couples the interior portion and an ambient environment, at least a portion of the passageway being defined by the housing cover.