Bearings are what enable the gears to rotate easily. They are typically produced outside of bronze or brass, they usually suit into races (or grooves) within the gearbox housing. Contaminants can enter your gearbox oil through vents or even the fill tube during checking/filling. Usually, having said that, contaminants are https://donovanwvsrq.blogspothub.com/33200134/detailed-notes-on-filter-gearbox