A transmission shaft assembly for a rolling stand for use in a metal rolling mill. The transmission shaft assembly transmits lubricant through the assembly. The transmission shaft assembly includes a shaft having an outer periphery and defining a centrally positioned longitudinal opening extending from a first end to an opposed second end of the shaft. The shaft defines a plurality of internal passageways in the shaft. The transmission shaft assembly also includes a rotary distributor mounted on the outer periphery of the shaft. The shaft assembly provides a conduit for the lubricant through the plurality of internal passageways in the shaft.