Valve body shift valves are operated by which of the following?

Valve body shift valves play a crucial role in the operation of an automatic transmission by directing hydraulic fluid to the appropriate clutches and bands, thereby facilitating the shifting of gears. The operation of these shift valves is influenced by various pressure sources within the transmission system.

Throttle valve pressure is generated by the movement of the throttle pedal and reflects the driver's demand for power. This pressure affects shifting, allowing for quicker shifts under acceleration and altering the shift points based on driving inputs.

Line pressure is the overall hydraulic pressure in the transmission system, responsible for engaging and disengaging clutches and bands. This pressure must be maintained at a certain level to ensure proper operation of all components, including the shift valves.

Governor pressure is derived from the transmission's speed and provides feedback regarding vehicle speed, influencing shifting behavior under different driving conditions.

Since the shift valves are indeed operated by throttle valve pressure, line pressure, and governor pressure, the correct answer is that all three sources work together in the operation of the valve body shift valves. Understanding these pressures enables mechanics to troubleshoot and optimize transmission performance effectively.