This awesome bit of gearing has appeared on HowStuffWorks prior to. You may realize it from the electrical screwdriver post. An automatic transmission is made up of two total planetary gearsets folded with each other into one particular element. See How Gear Ratios Operate for an introduction to planetary gearsets. https://gearboxauto64061.blogofoto.com/65320320/the-smart-trick-of-gearbox-auto-that-nobody-is-discussing