4 speed ratio transmission gearbox with differentail and installed on rear axle  

engine is from 250cc-- 1100cc. 

Differential is used on shell style tricycle axle,with 3 forward speed and 1 reverse speed

Forward Ratio:10:31,15:35,4.66:31, 

Reverse ratio:4.56:31 

Output side Spline teeth No. 19,22,32 

Below picture are the installation of the rear differential. 

Weight:24kg 

cast iron shell,with strong load capacity 

4 speed differential gearbox