The aforementioned friction bands and clutches are managed utilizing automatic transmission fluid (ATF), that's pressurized by a pump then directed to the suitable bands/clutches to obtain the necessary gear ratio. 1 (also labelled "L"): Restricts the transmission to 1st gear only, often known as a "small gear". This is helpful https://gearboxauto86296.bloggazza.com/32770367/gearbox-auto-for-dummies