The worm gearbox makes use of a significant diameter warm wheel. A worm or screw meshes with tooth within the outer circumference from the gearbox. Manual transmission gearboxes have a clutch that engages and disengages the motor through the gearbox, plus a gear shift lever that selects unique gears. https://gearbox18641.sharebyblog.com/33633734/detailed-notes-on-gearbox