According to the characteristics of lower fuel consumption of low speed engine, torque converters with lower speed and highcapacity were developed. CATIA was used to model by applying similar principles. Flow field analysis and modification were done with ANSYS. Rapid prototyping(RP) manufacturing technology was used for trial manufacture. And experiments were conducted in laboratory. The results show that loader matched with the two kinds of torque converters (YJSW3158A and YJZ340) can save 10% or more diesel than that matched with conventional torque converters, and manufacturing cycle is shortened, manufacturing difficulty and cost are decreased.