A lubrication system and method for an engine arc provided. In some embodiments, the lubrication method comprises driving a lube pump with a gearbox in a power drive housing, the gearbox including an expander shaft of an expander of a waste heat recovery system; suctioning lubrication fluid, with the lube pump, from a lube sump in the power drive housing; lubricating, with the lubrication fluid, an expander shall bearing supporting the expander; and after lubricating the expander shall bearing, transferring the lubrication fluid to the lube sump waste heat recovery power drive and lubrication system therefor.