In the event of sliding mesh gearbox, the output shaft gears continuously rotate Along with the output shaft while in other gearbox, the output shaft gears are mounted with bearings hence these gears rotates separately. Sensors in automatic transmissions use internal oil stress to shift gears at the right time. https://gearbox-auto31963.ttblogs.com/13446783/not-known-details-about-gearbox-auto