This wonderful piece of gearing has appeared on HowStuffWorks before. You might realize it from the electric screwdriver post. An automatic transmission is made up of two full planetary gearsets folded collectively into 1 part. See How Gear Ratios Work for an introduction to planetary gearsets. They are splined to https://charlievglmm.topbloghub.com/40484745/5-essential-elements-for-gearbox-auto