How the Transmission Works

There are two types of transmissions in the world of cars: manual and automatic. One, you control the gears that an engine uses to go, and one where the engine controls the gears that make it go. There are pros and cons to either one. With a manual transmission, you are able to speed up the engine, and put it in a gear from a different spot than you are at. For Example, you can begin in 3rd gear and the engine will shoot off like a bullet. Where as the automatic has to catch up to the gear. Also, the automatic allows you to do a lot more things and not have to pay attention to the car itself. So how does an engine and the gears actually work?

An engine is very much like a 12 speed or 18 speed bike. It has an initial speed in which it goes, this is the speed of the pistons going up and down. However, you can't be at full speed all the time, that is impractical and will blow up your engine. This is where the transmission comes in. The transmission changes the speed in which the engine is going by changing the gear to piston ratio. It moves one gear that is being used, takes the gear out of the housing, and replaces it with a "faster" gear. When the engine is running as fast as the pistons are, it is at the highest gear possible. These setting and reseting gears is what happens when you change gears.

In an automatic, the gears change according to the speed of the engine. No matter how much gas you dump in the engine by pressing the accelerator, the gears will only change as the speed of the engine hits the right rpms to allow the gears to change. The gears are set up to lock and unlock at specific rpms, and only those rpms. So if the engine is screaming at 10,000 rpms(red line), but the the car is only going at 2000, the car will stay in 2nd. This is why when you stomp on the gas pedal of an automatic, are you're going to get is a loud noise, and very jerky movements, till the rpms of the car and the engine match.

With a standard transmission, or what is called a stick shift you are controlling this gear changing process. To put it in its most simple form, the engine is already spinning, and the movement of the car is at a certain speed or rpm. The clutch pulls the gear that it is using out of the transmission. Keep in mind the tranny is spinning. Then the stick selects another gear to be used, and places it in front of the clutch to put it back in. However, that gear must be spinning at the speed of the engine, so the accelerator speeds up the gear to the new gear setting, and when it goes back in, it is spinning at the same speed. All of this happens when you change gears from 1st to 2nd. The engine is now allowed to go faster and put more speed into the car itself.

If you pull the clutch before the gear is in place, it will shove a gear into the housing at the wrong time and the gear teeth will not mesh correctly, this is called grinding the gears; because you are literally griding the gears together. That is the simplistic explanation of how a manual and automatic transmission work.