This awesome piece of gearing has appeared on HowStuffWorks just before. You could possibly understand it from the electrical screwdriver post. An automatic transmission has two full planetary gearsets folded alongside one another into a single ingredient. See How Gear Ratios Do the job for an introduction to planetary gearsets. https://gearboxauto17305.bloguerosa.com/33123023/top-latest-five-gearbox-auto-urban-news