AMSOIL Automatic Transmission oil, ATF and ATL must do the following: They must act as a hydraulic fluid, deliver correct friction requirements, protect gear wear and fight transmission heat. Manual Transmission Oils must- provide smooth shifts, fight wear and protect the brass synchronizers. In 2006, 18% of the vehicles made had manual transmissions. In 2018 only 2% of the vehicles made had manual transmissions.  This article discusses the differences between “automatic” and “manual” transmission fluids. Good article!