Bearings are what enable the gears to rotate effortlessly. They are typically created away from bronze or brass, plus they in good shape into races (or grooves) within the gearbox housing. Synchro rings have teeth on them that mesh with the teeth over the gears, plus they even have friction https://codyvaccd.bloggazzo.com/33166792/the-definitive-guide-to-filter-gearbox