Bearings are what enable the gears to rotate effortlessly. They are generally built away from bronze or brass, plus they fit into races (or grooves) in the gearbox housing. Contaminants can enter your gearbox oil as a result of vents or the fill tube for the duration of examining/filling. More https://filter-gearbox42074.bloggerswise.com/41478692/filter-gearbox-things-to-know-before-you-buy