The first transmissions were manual. This required the driver to shift between gears so that a vehicle can be speeded up or slowed down while the engine rotated within an optimum speed range. For many decades, manual transmissions were tricky to drive but good enough for most drivers. Some just never liked the coordinated shifting and clutching procedure involved, though. The car manufacturers were quite cognizant of this issue, and as a result, many were privately experimenting with self-shifting transmissions during the 1930s.