Manual transmissions (variously referred to as "stick-shift" or "straight-shift" usually have a foot-operated clutch pedal and a movable gear stick. Generally, automotive manual transmissions permit the driver to select any forward gear at any time, but motorcycles and many types of racing cars have Sequential transmissions, which will only permit the driver to shift to the next-higher or next-lower gear.
Manual transmissions typically have gear ratios that are selectable by locking specific gear pairs to the output shaft that is inside the transmission. In contrast, most automatic transmissions feature epicyclic or planetary gearing controlled by brake bands and/or clutch packs to select gear ratio.
Contemporary automobile manual transmissions typically have between four to six forward gears and a single reverse gear, but some manual transmissions have as few as two or as many as eight gears. Transmissions in heavy trucks and other heavy equipment often have at least 9 gears so the transmission can provide both a wide range of gears and close gear ratios to keep the engine operating within the power band. Some heavy equipment transmissions have dozens of gears, but many of those gears are duplicates, created either as an accident of combining gear sets, or intended to simplify shifting. Some manual transmissions are identified by the number of forward gears they offer (for example, 5-speed) as a way of distinguishing between automatic or other available manual transmissions.
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