Bearings are what enable the gears to rotate smoothly. They are typically created away from bronze or brass, plus they in good shape into races (or grooves) from the gearbox housing. Fundamentally it is made of a steel plate with mesh-kind inserts that reduce contaminants from getting into the transmission https://filtergearbox15789.blogthisbiz.com/40928890/filter-gearbox-fundamentals-explained