This amazing bit of gearing has appeared on HowStuffWorks before. You could possibly realize it from the electrical screwdriver post. An automatic transmission has two total planetary gearsets folded together into one ingredient. See How Equipment Ratios Work for an introduction to planetary gearsets. This engineering has existed for long https://gearbox-auto64184.answerblogs.com/34363288/new-step-by-step-map-for-gearbox-auto