This paper describes the sequential development of both multipurpose and universal oils for agricultural tractors. “Universal oil” infers the concept of one oil to lubricate the tractor including engine, drivelines, oil-immersed brakes, if fitted, and farm equipment whereas a “multipurpose oil” lubricates drivelines, brakes, and equipment but not the engine. Such rationalization is desirable both to the user and to the oil supplier. Moreover, it has proved technically feasible to meet the requirements of most major manufacturers' tractors in service.Successful rationalization depends upon careful selection of additives and comprehensive testing in rigs and tractors.Multipurpose formulations must have specific frictional characteristics for lubricating both immersed disc brakes and immersed power takeoff clutches and load-carrying and antiwear properties for gearing, pumps, and bearings, etc. Equally important are oxidation-corrosion stability, seal performance, rheology, and other related chemical and physical properties. The universal oil must provide for all the preceding driveline requirements and in addition lubricate the engine. The problems arising from such developments and the ways in which the difficulties have been overcome are explained.