In order for an engine to send its rotational energy from the crankshaft to the transmission, a device must act as an intermediary, since these two devices (the engine and transmission) will be rotating at different speeds. This is accomplished primarily by a clutch in manual vehicles, and by a torque converter in automatic vehicles. First, let's find out how a torque converter works.
Now that we understand how automatic vehicles transmit power, let's take a look at manual vehicles, which use clutches.
Some vehicles use multi-plate clutches, since they require a large amount of torque to be transmitted, or because they need to be small. Multi-plate clutches are common in motorcycles for their size advantage.
There are other types of clutch systems as well, such as a dual clutch transmission. Check out the lesson on transmissions and gears for more information on how a dual clutch transmission works, and to find out how the power continues to pass along the drivetrain.