An automatic transmission seems pretty simple ... A central gear is called the sun gear, while smaller planet gears revolve around it, held in a ring called a planet carrier.

Almost every vehicle with an automatic transmission sold today uses letter codes to represent the different gear modes. Each mode is usually self-explanatory, such as “D” for Drive or “R” for Reverse.

When did you last think about what goes on under the hood while cruising down the freeway in your trusty automatic ride? As you relax and enjoy the open road, the intricate dance of gears is ...

As a key player in the functionality of automatic transmission systems—alongside the planetary gears, clutches, and torque converter— the valve body functions as the control center of the gearbox.