A transmission PTO is a type of power take-off. A power take-off is a splined device that connects an implement to the transmission of a machine, usually a tractor. It allows power to be transferred from transmission to the implement.
One of the first types to be developed, the transmission PTO connects a machine's transmission directly to an implement. The transmission of a tractor, for example, would be directly connected to a mower blade or other attachment via the transmission PTO, enabling the mower to utilize the power generated from the tractor’s transmission.
Although the device provides farmers and construction workers with the advantage of simply attaching a device to their main machine, there are some drawbacks. The transmission type sometimes requires an overrunning clutch to prevent the implement from straining the PTO and the transmission. The clutch takes the pressure off the main equipment by rotating the shaft in one direction. The main disadvantage occurs when the tractor or equipment is not in gear or is in the process of slowing down. When this occurs, the PTO will cease operation until the clutch is released. This feature is currently being updated as more manufacturers are incorporating the PTO into new tractor models.