The transmission shift lever assembly can be moved to cause movement of the shift linkage, shift forks, and synchronizers. The shift lever may be either floor mounted or column mounted, depending upon the manufacturer. Floor-mounted shift levers are generally used with an internal shift rail linkage, whereas column-mounted shift levers are generally used with an external rod linkage.
Manual transmission has a three, four, five and a reversal gear to change the speeds of the car. Each combination of gears has an appropriate number of teeth to provide the desired reduction of the output shaft speed relative to that of the input shaft. It all depends on the gear ratio also if the ratio is three: five then the engines crankshaft will turn three and a half times for each revolution of the transmission is in the first gear. The sliding shift forks accomplish the selection of gears through the driver controlled gearshift lever.
Overdrive is an arrangement of gearing which produces more revolutions of the driven shaft than the driving shaft. The engine RPM will be reduced by at least thirty percent while the car maintains the same road speed. The fuel burning up will be reduced and the engines life will be extended. There are some other types of gears call planetary gears that are used in the overdriven transmissions. The planet gears each turn on their own alignment while rotating around the central gear. A ring gear surrounds all these gears also.
The planetary gears are used as a reduction gear for the reverse and are used in multiple sets where more than two forward speeds are desired. It produces more revolutions of the driven shaft then the driving shaft. The planetary gears are in a mesh at all times they are never shifted in or out of engagement. The gears are attached to different drums that are attached to other in use parts of the system. This makes the gears to be used in a way as the different drums are held from rotation by the brake bands that are attached to them.
