This correspondence course, originally developed for the Marine Corps, is designed to provide mechanics with an understanding of the operation, maintenance, and troubleshooting of automotive power trains and certain auxiliary equipment. The course contains six study units covering basic power trains; clutch principles and operations; conventional transmissions; transfer assemblies; universal joints, propeller shafts and other joints; and final drives, differential assemblies, and axle assemblies. Each study unit begins with a general objective, which is a statement of what the student should learn from the study unit. The study units are divided into numbered work units, each presenting one or more specific objectives, and illustrated unit texts. At the end of the unit text are study questions with answers. A review lesson completes the course. (KC)