What is the function of the hydraulic system in an automatic transmission?

The function of the hydraulic system in an automatic transmission is essential for the proper operation of the transmission’s internal components. It primarily serves to engage and disengage clutches and bands, which are critical for controlling the transfer of power from the engine to the wheels. The hydraulic system uses pressurized transmission fluid to create the necessary force to operate these components automatically based on vehicle speed and load conditions.

When the vehicle is moving, the hydraulic system adjusts the pressure in various circuits to control the engagement of clutches and bands within the transmission. This allows for smooth shifting between different gear ratios without the need for driver intervention, facilitating efficient performance and enhancing the driving experience. The proper operation of this hydraulic system is vital since it directly influences the transmission's ability to shift gears seamlessly and deliver power effectively.

While the other choices relate to different functionalities, they do not pertain directly to the core role of the hydraulic system within an automatic transmission. For instance, cooling the engine is a function of the engine cooling system, constant power delivery isn't directly associated with the hydraulic system, and manual gear shifting pertains to a driver-operated mechanism rather than the automatic control offered by the hydraulic system.