Transmission Systems

Abstract

The transmission has to transfer power from the engine to the road wheels in order to propel the vehicle. The essential components are a clutch or hydraulic coupling (to isolate the engine from the transmission), a gearbox (to allow the vehicle speed range to be greater than the engine speed range and to provide load matching) and a differential (to allow relative rotation of the driven wheels during turns). The differential can be remote from the gearbox and form part of the rear axle. In front-engined front wheel drive vehicles and in rear-engined real wheel drive vehicles, the gearbox and differential can be combined: an arrangement that is sometimes referred to as a transaxle. In high-performance vehicles with the engine at the front, the gearbox is sometimes incorporated into the back axle in order to improve the weight distribution.