<P> A torque converter is a type of fluid coupling which transfers rotating power from a prime mover, like an internal combustion engine, to a rotating driven load . In a vehicle with an automatic transmission, the torque converter connects the power source to the load . It is usually located between the engine's flexplate and the transmission . The equivalent location in a manual transmission would be the mechanical clutch . </P> <P> The key characteristic of a torque converter is its ability to multiply torque when the output rotational speed is so low that it allows the fluid coming off the curved vanes of the turbine to be deflected off the stator while it is locked against its one - way clutch, thus providing the equivalent of a reduction gear . This is a feature beyond that of the simple fluid coupling, which can match rotational speed but does not multiply torque, thus reduces power . </P> <P> Some of these devices are also equipped with a "lockup" mechanism which rigidly binds the engine to the transmission when their speeds are nearly equal, to avoid slippage and a resulting loss of efficiency . </P> <P> By far the most common form of torque converter in automobile transmissions is the hydrokinetic device described in this article . There are also hydrostatic systems which are widely used in small machines such as compact excavators . </P>

How does a torque converter lockup switch work
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