The aforementioned friction bands and clutches are controlled using automatic transmission fluid (ATF), that is pressurized by a pump and then directed to the appropriate bands/clutches to acquire the expected gear ratio. 1 (also labelled "L"): Restricts the transmission to 1st gear only, often called a "very low equipment". This https://gearboxauto86296.bloggazza.com/32770367/gearbox-auto-for-dummies