Abstract: A hub clutch assembly is designed so that fluid pressure is used only while the driving mode is being changed over between a four-wheel position and a two-wheel drive positions, while eliminating the necessity of holding a coupling member in position once the driving mode has been changed over. A driven member and a driving member are coupled together and uncoupled from each other by a slider which is moved under a negative or positive air pressure. A spring is used to maintain the slider in the drive position, while a magnet is used to maintain the slider in the four-wheel drive position.