Abstract: A lubricant supply system for a gearbox includes a lubricant flow circuit having, in fluid flow sequence: a variable-flow rate first pump; an lubricant cooler; and a gearbox. The system also includes: a first temperature sensor for sensing a temperature of lubricant circulating within the lubricant flow circuit; a pressure sensor for sensing a pressure of lubricant circulating within the lubricant flow circuit; and a controller operably connected to the pressure and temperature sensors and to the first pump. The controller is operable to control flow of the pump in response to the sensed temperature and to the sensed pressure.