A non-synchronous transmission— also called a crash gearbox— is a sort of manual transmission supported gears that don’t use synchronizing mechanisms. They require the motive force to manually synchronize the transmission’s input speed (engine RPM) and output speed (driveshaft speed).

Non-synchronous transmissions are found primarily in various kinds of industrial machinery, like tractors and semi-tractors. Non-synchronous manual transmissions are found on motorcycles, within the sort of constant-mesh sequential manual transmissions. Before 1960, most cars used constant-mesh but non-synchronous transmissions.

Some commercial applications use non-synchronized manual transmissions that need a talented operator. Looking at the country, many local, regional, and national laws govern the operation of those kinds of. This class may include commercial, military, agricultural, or engineering vehicles. a number of these may use combinations of types for multi-purpose functions. An example could be a power take-off (PTO) gear. The non-synchronous transmission type requires an understanding of substances range, torque, engine power, and multi-functional clutch and shifter functions. Also see the Double-clutching, and Clutch-brake sections of the most article. Float shifting is that the process of shifting gears without using the clutch.