Dog clutch skids on the leading shaft to rotate with it. All the equipment over the layshaft is fastened with it.  If the left-hand dog clutch is brought to skid on the left in the gearshift lever, it messes with the clutch gear, along with the higher-speed equipment is achieved. https://elliottfslam.dailyhitblog.com/39213540/what-does-gearbox-auto-mean