The worm gearbox employs a substantial diameter warm wheel. A worm or screw meshes with tooth about the outer circumference with the gearbox. Manual transmission gearboxes Have got a clutch that engages and disengages the engine from the gearbox, and also a gear shift lever that selects distinct gears. https://gearbox47801.blogocial.com/gearbox-an-overview-69563711