Transmission casing including a hydraulic clutch

A transmission casing including a hydraulic clutch for a working vehicle in which said transmission case includes a lateral opening, a cover attachable to said transmission casing for closing said lateral opening, said hydraulic clutch being disposed on a transmission shaft within said transmission casing, a hydraulic control means mounted on an inner face of said cover attached to said transmission case, said hydraulic control means acting to control oil flow to said hydraulic clutch, said hydraulic control means being connectable to oil passage means connected to said hydraulic clutch when the cover is attached to said transmission case, said hydraulic oil passage means includes a first oil passage operatively connected to the hydraulic clutch, a second oil passage defined in a stationary member disposed adjacent said transmission shaft and communicating with said first oil passage and a third oil passage defined in an oil pipe adapted to extend between said stationary member and said hydraulic control means to hydraulically connect said second oil passage to said hydraulic control means.