Bearings are what enable the gears to rotate smoothly. They are typically built outside of bronze or brass, and they in shape into races (or grooves) while in the gearbox housing. Tough shifting, minimized fuel efficiency, and burning smells are only many of the indicators of a bad transmission filter. https://filter-gearbox41628.izrablog.com/34597185/facts-about-filter-gearbox-revealed