Transmission case cover, transmission and vehicle

The utility model provides a speed changer shell cover, a speed changer and a vehicle, the speed changer shell cover comprises a shell body which is provided with a containing cavity, and the containing cavity is used for containing an operation part; the drainage rib is arranged on the side wall face of the containing cavity, and one end of the drainage rib extends to the position above the operation component, so that lubricating oil in the containing cavity is suitable for flowing to the operation component along the drainage rib. According to the speed changer shell cover, the drainage ribis arranged on the side wall surface of the containing cavity, and one end of the drainage rib extends to the position above the operation component, so that when the operation mechanism operates, splashed lubricating oil in the speed changer shell can be gathered on the drainage rib and flows back to the operation component under the action of gravity, the lubricating requirement of the operation component is guaranteed