Abstract: An apparatus for controlling a downhole drilling motor assembly includes a tubular housing having an interior sidewall which defines an interior bore. A mandrel is rotatably mounted within the interior bore of the housing. The mandrel has an exterior surface. A hydraulic dampener assembly is disposed between the interior sidewall of the housing and the exterior surface of the mandrel. The hydraulic dampener assembly limits the rate of rotation of the mandrel within the housing, thereby providing a preset resistance to reactive torque. The described apparatus can also be used as a steering tool by the addition of a feature that selectively blocks the flow of hydraulic fluids through the hydraulic dampener, thereby locking the mandrel in a selected directional position.