Because the transmission has greater force when working in first gear and reverse gear, both the lower and reverse gear of the two-shaft transmission and the intermediate shaft transmission should be arranged at the support near the shaft in order to reduce the shaft deformation, ensure that there is not too much reduction in gear contact, and then arrange each gear in the order from low to high gear stops. This will allow the shaft to be sufficiently rigid and easy to assemble. The transmission ratio of reverse gear is close to that of first gear, but because the time of using reverse gear is very short, some schemes arrange first gear on the support near the shaft.