The lubricating oil covered by this specification is intended for the crankcase lubrication of reciprocating spark-ignition and compression-ignition engines used in all types of military combat/tactical ground equipment. The oils are also intended for the same application in power transmissions, hydraulic systems, and non-hypoid gear units of engineer/construction equipment, materials handling equipment and combat/tactical ground equipment. The specification product is intended for crankcase lubrication under all conditions of service, as defined by appropriate lubrication orders, when ambient temperatures are in the range shown in table IV. In addition the lubricating oil covered by this specification is intended for use in arctic regions as an all weather (year-round) power transmission fluid for military combat/tactical ground equipment. The lubricating oils covered by this specification meet service classifications API CG-4, CF of SAE J183 and are intended for all conditions of operational service, as defined by appropriate lubrication orders. The lubricating oil under this specification can be used at all temperatures for transmission, hydraulic, and non-hypoid gear applications provided the use of the arctic grade is warranted for winter operations, otherwise, the appropriate grade under MIL-PRF-2104 is the recommended choice for these applications (see 6.7). This specification requires an oil formulation that is both versatile (used as engine oil, transmission fluid, and hydraulic fluid) and meets extreme operating conditions for use in combat/tactical ground equipment. These requirements cannot be found in current industry standards and are not appropriate for other government vehicles.