Power take-off unit with automatically actuated drag brake

A power take-off unit includes a drag brake assembly that is automatically engaged when a hydraulically actuated clutch assembly is disengaged. The drag brake assembly includes a brake piston (33) that is axially aligned with the output shaft (13) and is urged into frictional engagement therewith by a spring. When pressurized fluid is provided, the clutch assembly (23,24) is engaged to cause the output shaft to be rotatably driven by the input gear (12). At the same time, the pressurized fluid causes the brake piston (33) to retract axially within the cylindrical recess against the urging of the spring. As a result, the brake piston is moved out of frictional engagement with the output shaft to permit free rotation of the output shaft. When pressurized fluid is not provided, the clutch assembly (23,24) is disengaged to prevent the output shaft from being rotatably driven by the input gear. The lack of pressurized fluid in the clutch chamber allows the spring disposed within the cylindrical recess to urge the brake piston axially into frictional engagement with the output shaft to retard rotation thereof.