Auto Questions: How Do Manual Transmissions Work?

The basic parts of a manual or stick transmission and how they work to switch gears and make your automobile accelerate and reverse.

Have you ever gotten into your auto, started the engine with the key, pushed the clutch in, and shifted it into gear to drive down the road? Of course you have, if your auto has a manual transmission. But, have you ever wondered how that type of transmission makes your auto move? Probably not, but it's a good thing to know the basics of how your auto works.

The engine, of course, provides the power, (or the torque) to run your auto, but the manual transmission furnishes the means for the power to be transferred to the axles and the wheels. The transmission accomplishes this task by using a series of gears that are connected together. Each gear has a different ratio, and these ratios make the axle and the wheels of an auto turn at a rate of speed that differs from the speed or the torque of the engine. To better understand this, you must realize that an engine can only reach a certain speed by accelerating it.

But when an engine is attached to a manual transmission, the gears allow the auto to move in different speeds, according to the gear we have the transmission shifted into, and the amount of acceleration we give the engine.

There's another device that a manual transmission needs to work, and this device is called a "clutch". The clutch is attached to the engine of an auto, as well as to the manual transmission.

When the driver presses down on the clutch lever inside the auto, this action causes the two pieces of the clutch - the plate, which is attached to the engine, and the lining, which is attached to the manual transmission, to lose contact from each other. Without this contact, the engine and the transmission are not connected. Therefore, the auto cannot move. But, when you have the auto shifted into gear, and you slowly release the clutch pedal, the two parts connect together again, and the auto is able to move again through the use of the gears in the transmission and the power from the engine. A "slipping" or worn out clutch is usually the biggest maintenance problem associated with a manual transmission. It usually wears out faster than the actual transmission does, especially if the driver of the auto doesn't operate the clutch properly.

Learning to drive an auto that uses a manual transmission is relatively easy. Once you learn how to engage the clutch, shift the transmission into gear, then gently release the clutch pedal while you begin to slowly accelerate the engine, you have mastered the basics.

But, what happens when the auto is in motion and the driver needs to change a gear in order to move faster? This is where you must learn how when to shift and when not to. Of course, once the auto is moving forward, you should never, ever shift into "reverse" without first stopping the auto first. If the auto is in first gear, for example, and you're cruising down the road, when you reach a certain rate of speed, the manual transmission will have to be shifted to a higher gear in order for it to work properly. Therefore, the driver quickly engages the clutch by pushing the clutch pedal down as far as it will go. Again, this action causes the engine and the manual transmission to lose contact with each other. The gear shifter is then shifted to the next highest gear. Then, when the clutch is disengaged, it allows the engine and the manual transmission to be connected again, and the gear change allows the auto to move faster.

© High Speed Ventures 2011