This is 3rd Custom gearbox for Baja ATV buggy(Team Saksham International), before staring 3D modelling for this project, rigorous calculation and research is performed by me. as this gearbox needed to perform national and international events, the designing is done keeping the efficiency and performance as the utmost priority and also it needs reliable for harsh testing, the gearbox uses Spur gear made of AISI4340 followed by further heat treatment, and the gearbox casing is designed of aircraft-grade aluminium 7075-T6. this gearbox only weighed 3.72 kgs(dry) lightest ever by any Indian Baja team( without using titanium or carbon fiber composite).