The pinion attaches to the transmission axle and is used to interact with the drive wheel gear to rotate the wheel.
Consult your owner's manual for proper part number identification and proper installation
(2) Genuine OEM Toro Gear Pinions. Fits 20, 22" Inch / 50, 55 cm Recycler Push Lawn Mower It is the customers responsibility to make sure this is the correct part for their unit.