12 parts for land vehicles, namely, torque-transmitting clutches and their components, namely, clutch discs, mechanical and hydraulic control elements sold as a unit; ball valves and cone valves, pistons, housings, shafts, hubs and spacers, sold as a unit; fluid pumps and their components, namely, feed plates, mechanical and hydraulic control elements, ball valves and cone valves and pistons, sold as a unit, aggregate units composed of torque-transmitting clutches and fluid pumps for operating them; limited slip differentials and distributor gears