Abstract: A controller for the hydraulic clutch of two speed auxiliary transmission connected in series with the main transmission and engine of a vehicle wherein the hydraulic clutch is applied for the higher speed drive and released for the lower speed drive which is through a one-way clutch that overruns in the higher speed drive operation. The controller is responsive to engine throttle opening to apply the hydraulic clutch for throttle openings below a predetermined amount to allow braking of the vehicle by the engine during deceleration rather than coasting by the overrunning of the one-way clutch.

Abstract: A vehicular transmission in which a multiple speed manual transmission of the two parallel shaft type has an auxiliary transmission connected in series between the two shafts for some of the multiple speeds. The auxiliary transmission providing a high speed and a low speed. The auxiliary transmission includes gearing for providing the high or low speeds to the gears on one of the shafts. A hydraulic clutch and a one-way clutch in said auxiliary transmission selectively connect the high or low speed gearing, with the one-way clutch engaging when the hydraulic clutch is disengaged and being overrun when the hydraulic clutch is engaged.