This awesome bit of gearing has appeared on HowStuffWorks prior to. It's possible you'll recognize it from the electrical screwdriver article. An automatic transmission has two full planetary gearsets folded jointly into just one component. See How Gear Ratios Work for an introduction to planetary gearsets. The automobile gearbox or https://gearbox-auto75285.blogrelation.com/40382792/examine-this-report-on-gearbox-auto