If you progress the change selector to some decrease gear, the transmission will downshift Except if the car is going also quickly for that gear. If the car is going too fast, it can wait around till the car slows down and after that downshift. The change valve is pressurized https://gearbox-auto27924.ampblogs.com/the-smart-trick-of-gearbox-auto-that-nobody-is-discussing-70494677