Second, there isn't a gear shift within an automatic transmission vehicle, so when you set the transmission into push, almost everything else is automatic. The handbook valve is what the shift lever hooks nearly. Dependant upon which gear is chosen, the guide valve feeds hydraulic circuits that inhibit particular gears. https://gearbox-auto08417.blogolenta.com/31099800/new-step-by-step-map-for-gearbox-auto