A park valve performs a multi-plexing function in which an out-of-park circuit is connected to line pressure when the valve is in an out-of-park position and is vented when the valve is in a park position. When particular clutches are released, the out-of-park circuit biases the park valve toward the out-of-park position. To initiate engagement of park, a controller commands a low line pressure, reducing the forces that bias the park valve toward the out-of-park position. Once the valve reaches an intermediate position in which the line pressure circuit is no longer fluidly connected to the out-of-park circuit, the controller commands an increase in line pressure, increasing the forces that bias the park valve toward the park position.