Hydraulically-actuated shift system for a transfer case

A transfer case for a motor vehicle having an engine and first and second sets of wheels, comprising:

• a first output shaft for transmitting drive torque from the engine to the first set of wheels for normally establishing a two-wheel drive mode;
• a second output shaft for selectively transmitting drive torque to the second set of wheels for establishing a four-wheel drive mode;
• a shift mechanism having a clutch sleeve fixed for rotation with said first output shaft and supported for movement thereon between a first position uncoupled from said second output shaft for establishing said two-wheel drive mode, and a second position coupling said second output shaft for rotation with said first output shaft to establish said four-wheel drive mode;
• a hydraulic actuator acting on said clutch sleeve;
• a source of pressurized fluid in communication with said hydraulic actuator;
• a mode select mechanism for permitting a vehicle operator to select one of said two-wheel drive and four-wheel drive modes and generate an input signal indicative thereof;
• and
• control means for controlling the flow of said pressurized fluid between said hydraulic actuator and said fluid source for selectively moving said clutch sleeve between said first and second positions in response to said input signal.