Have you ever asked yourself the question, “Are there any five-speed automatics that are actually six-speeds but they used to be four-speeds?” If so, read on for the answer. About a quarter-century ago, Jeep introduced its very first five-speed automatic transmission, found in the 2000 Grand Cherokee and mated to the likewise-innovative overhead-cam PowerTech 4.7-liter V8. But believe it or not, that five-speed gearbox was mechanically and physically identical to the four-speed found on the Grand Cherokee, differing only by shift strategies and transmission programming. How is that possible, you may ask? Through the magic of planetary ratios (and some just plain weird engineering).
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