Abstract: An apparatus for delivering air through a powered axle assembly for use in automatic tire inflation systems. The apparatus comprises a base attachable to a non-rotating structure within the axle assembly and having the drive axle extend therethrough. A rotor is mountable in the axle assembly for rotation with the drive axle and for forming an air chamber between the rotor and the base and extending about the drive axle. An annular sealing member in sealing engagement with the rotor and the base is disposed within the air chamber and is rotatable with the rotor and with respect to the base. The base includes at least one air inlet for delivering air in a radial direction into the air chamber and the rotor includes at least one air outlet for air flow out of the chamber.