Complete Overdrive Gearbox Assembly for Plunger or rigid Indian Chiefs from 1936 - 1953. Supplied with 25 tooth sprocket. Complete Overdrive Gearbox Assembly for Plunger Indian Chiefs from 1940 - 1953. Supplied with 25 tooth sprocket. You will also need to seal your Engine to primary and your Clutch to pimary and fit a breather to your Primary drive. All these parts are listed on this site https://crazyhorsemoto.com.au/products/crank-seal-primary-upgrade-kit-fits-earl?_pos=40&_sid=7b315b9e6&_ss=r https://crazyhorsemoto.com.au/products/00661003b-breather-for-primary-case?_pos=1&_sid=6b69b9a34&_ss=r https://crazyhorsemoto.com.au/products/jg-2372-sealed-transmission-kit?