The worm gearbox uses a large diameter warm wheel. A worm or screw meshes with teeth over the outer circumference in the gearbox. Manual transmission gearboxes Use a clutch that engages and disengages the engine with the gearbox, in addition to a gear change lever that selects various gears. https://gearbox19630.onesmablog.com/not-known-factual-statements-about-gearbox-74402595