The Hyperlogos

The word transmission refers to a transfer of something. In this case, that is kinetic energy. In basically every automobile, a rotational force (whether produced from a reciprocating motion, such as in a typical gasoline engine with pistons, or from a rotary engine, electric motor, or turbine engine) is both transmitted from the engine to one or more driven wheels, but it is also geared down (and sometimes also up) so that it can do useful work.

A magnetic drain plug has a magnet in the end of the plug to catch ferrous metal filings shaved away from the inside of the engine, transmission, differential, or some similar oil-lubricated assembly in order to reduce wear. This plug has a hole drilled through the wrench flats for attachment of a safety wire, which is often a requirement in racing.