When the computer decides the time is right, it disengages the clutch automatically, selects a completely new equipment then re-engages the clutch. In handbook transmission, the motive force should shift the gears manually by utilizing the equipment shifter. The below figure reveals The fundamental structure of your guide transmission gearbox. https://gearboxauto31739.uzblog.net/not-known-details-about-gearbox-auto-47879589