This remarkable piece of gearing has appeared on HowStuffWorks just before. It's possible you'll figure out it from the electrical screwdriver short article. An automatic transmission includes two entire planetary gearsets folded with each other into a single part. See How Gear Ratios Perform for an introduction to planetary gearsets. https://gearboxauto53061.targetblogs.com/34616277/the-smart-trick-of-gearbox-auto-that-no-one-is-discussing