Specialized training tool designed for hands-on learning in heavy vehicle transmission systems. This non-synchronized gearbox, commonly used in 300/400HP commercial vehicles, features a dual-section design with mechanical control for lower gears and pneumatic control for speed-select gears. The model includes chromed and galvanized components for durability and is mounted on a mobile stand for easy classroom use. Manual operation through a handwheel allows students to explore both mechanical and pneumatic control principles, while auxiliary shafts ensure equal stress distribution for enhanced understanding of gearbox durability.