Bearings are what enable the gears to rotate efficiently. They are generally manufactured outside of bronze or brass, and they suit into races (or grooves) from the gearbox housing. Synchro rings have enamel on them that mesh with the tooth over the gears, they usually also have friction resources on https://johnathanwwtoj.blogdiloz.com/33092937/an-unbiased-view-of-filter-gearbox