A manual transmission is also known as a stick-shift (in the United States), a manual gearbox, a manually operated transmission, or a standard transmission. This type of transmission system for automobiles uses a driver-operated clutch that is usually engaged or disengaged by a hand lever, or most commonly by a foot pedal.
This type of vehicle transmission is the one with a stick or lever for shifting gears and a third pedal to operate a clutch.
But do you know how a manual transmission works? And how it differs from an automatic transmission?
There are still more modern manually operated cars in the automotive industry that are being sold. Now, modern shift-stick cars can have as many as seven or eight speeds but they remain similar through-and-through.
This article will take you further to the ‘magic’ of a manual gearbox. This write up will let you explore how a manual transmission works, the difference between automatic and manual transmissions, manual transmission types, the leading manual transmission cars of 2019, and other facts about a standard transmission system in cars.
So stay on the edge of your seat and better continue reading!
What is a manual transmission?
manual transmission care my car
The manual transmission in cars is still one of the widely used transmission systems in the world. We do all know that the engine of a vehicle creates rotational (or spinning) power. To run your car, it needs to transfer that spin power to the wheels from the drive shaft.
To transmit the rotational energy (kinetic energy) to the wheels of the car, this is where the transmission system takes in. But how can you change the speed of the car without changing the speed of the engine? It’s so easy, the transmission changes the gear ratio to accelerate or slow down the car.
In a manual transmission, the flywheel is connected to the engine’s crankshaft and rotates along with it. The clutch disc is located in-between the flywheel and the pressure plate. The two are held against each other under pressure.
When you run the engine and you pressed the clutch, the flywheel rotates the clutch plate and here the transmission takes place. The changing of gear ratios happen by pressing the clutch foot pedal while your one hand selects the gear. We will discuss later how the clutch, gears, synchronizer collars, and other parts of a manual transmission are utilized to run a car.
Basic parts of a manual transmission system in a car
Remember that a manual transmission drivetrain should not be confused with a power steering mechanism. To know how manual transmissions in vehicles work, it is best to know more about the parts and elements that make up this system. We will enumerate here the basic parts of a manual transmission system of a vehicle:
1. Clutch
The clutch is that part of the transmission system that works to engage and disengage the drive shafts’ moving elements. The clutch lies in-between the engine and the gearbox of the transmission.
When the clutch is depressed, it disconnects the power flow between the engine and the transmission gearbox but allows the engine to run. During this time, shifting gears is easier and avoid damage to the gears.
2. Input shaft
The input shaft spins the same as the engine speed on which its power and torque come from.
3. Output shaft
Running parallel to the countershaft, the output shaft delivers power to the rest of the drivetrain within the transmission system. This shaft runs above the countershaft and has its set of gears where its power output depends on which gears are meshed on it. This shaft has free-rotating gears mounted on it by fully-lubricated ball bearings. Its speed is determined by what gear (first to fifth) is engaged on it.
4. Counter-shaft
The countershaft, also known as ‘layshaft’, lies below and runs parallel to the output shafts. It is directly linked/connected to the input shaft via a fixed speed gear.
The countershaft rotates with the same speed as the input shaft and spins with it whenever the input shaft spins. The countershaft has all the gears (1st-5th) that receive power from the input shaft including the reverse gear.
5. Counter-shaft
The countershaft, also known as ‘layshaft’, lies below and runs parallel to the output shafts. It is directly linked/connected to the input shaft via a fixed speed gear.
The countershaft rotates with the same speed as the input shaft and spins with it whenever the input shaft spins. The countershaft has all the gears (1st-5th) that receive power from the input shaft including the reverse gear.
6. First to Fifth gears (1st-5th gears)
These gears are mounted to the output shaft via ball bearings. These toothed gears determine what ‘gear’ you are using and they all spin constantly. Each gear is always enmeshed and spinning with one of the gears on the countershaft.
Most modern vehicles have this set of gears and their constant meshed arrangement is what you can find in synchronized transmissions or constant mesh transmissions. All of these gears spin at the same time but only one of them is delivering power to the drivetrain using synchronizer collars or sleeves (more about this later).
7. Idler gear
The idler gear, as the name implies, is an stationary gear that allows your car to go in reverse. This gear, which is sometimes called the ‘reverse idler gear’, lies in-between the reverser gear on the output shaft and a gear on the countershaft.
This idler gear is the only gear in the transmission system that isn’t always spinning together with the countershaft as it only rotates when you bring the car in to reverse.
8. Shift fork
This element holds the synchronizer collar.
9. Shift rod
Most 5-speed manual transmission cars have 3 shift rods. These rods enable the synchronizer collar to move towards the the gear you want to engage. A shift rod’s end is connected to the gearshift while at the other end, a shift fork is connected that holds the collar.
10. Synchronizer collars or sleeves
Most modern manual transmission cars nowadays have a synchronized transmission. This suggests that the gears delivering power on the output shaft are constantly linked or enmeshed with the gears on the countershaft and they are spinning at the same time. But only one of these gears actually deliver power to the transmission.
11. Gearshift
The gearshift or stick is the one you move to put the vehicle in a gear.
Fig. 1: Basic Parts of a Manual Transmission System
What are Gear Ratios?
A manual drivetrain has sets of gears inside the transmission with various sizes. But unlike auto transmission, a shift-stick transmission don’t have planetary gear set. What you have in a manual transmission system are a series of toothed gears with different sizes.
What you have in a manual transmission is an input shaft from the engine that is connected to the output shaft that drives the wheels. Underneath this shaft is the countershaft and both these shafts have gears on them.
This varying sizes of gears can increased or decreased torque without changing the speed of the engine. This is all because of gear ratios, which represent the gear’s correlation to each other in size. If different sizes of gears mesh together(or engaged), the gears can rotate with varying speeds and provide different amount of power.
Most conventional manual transmission cars today have up to 4-speed transmission while some has a 5th gear (also called an ‘overdrive).
A typical 5-gear manual transmission car’s ratios
1. First Gear
The first gear is the largest in the transmission system which is enmeshed with a smaller gear. The common ratio when a vehicle is in the first gear is 3.166: 1. Engaging the first gear enables you to have a low speed but more powerful. This gear ratio is ideal for starting the vehicle.
2. Second Gear
With slightly smaller diameter than the first gear, the second gear is enmeshed with it (first gear). The second gear has usually with a ratio of 1.882:1, where the speed increases slightly but the power decreases.
The second gear is practical when starting on slippery surfaces. It is also ideal to use for engine braking when descending a steep hill. This gear is generally used for 5 mph to 15 mph.
3. Third Gear
The third gear is also enmeshed with the first gear and is slightly smaller than the second gear. It’s usual ratio is 0.972:1 and good for 15 mph to 30 mph speeds.
4. Fourth Gear
The fourth gear is slightly smaller than the third gear and is ideal for 30 mph to 40mph speeds. Also known as the ‘direct drive’, the fourth gear has a typical ratio of 0.972: 1, and spins with the same speed as the input shaft when your car is in this gear.
5. Fifth Gear
Also called as ‘overdrive’, cars with a fifth gear is usually enmeshed to a larger gear. This makes the fifth gear to rotate faster than the gear that is delivering power to the transmission. Its typical ratio is 0.78:1 and used for speeds above 40 mph.
Manual transmission vs automatic
Fg.2: Manual-transmission-and-automatic-transmission
There are two main differences between automatic and manual transmissions and you might not know these, until now.
The first difference is that an automatic transmission, there is no gear shift manually. Everything else comes automatically once you put the car’s transmission into drive. And second, an automatic transmission system doesn’t have a clutch pedal like in a manual transmission.
Know more about the differences between an auto transmission and a manual transmission here.
How a manual transmission works
Fg.3: Manual transmission works - Via: giphy.com
Now you know the basics (parts, gear ratios, etc.) of a manual transmission in a car, you might be eager to know how this transmission works? If you will know the basics of how a manual transmission works, it is easier to know how to drive a manual transmission car. So here it goes!
To start a manual transmission car, before you turn on the ignition key, you must disengage the clutch by pressing the clutch pedal. This action will disconnect the power flow between the input shaft and the transmission system that will allow the engine to run without transmitting power to the rest of the car.
Then, the gearshift can be moved to the first gear while the clutch is disconnected. The shifting rod in the gearbox will move the shifting fork towards the first gear. The first gear will enmesh with a gear connected with the countershaft ans spins at the same speed as that of the engine’s output shaft.
The shifting fork has a synchronizer collar which does two things:
It securely put the driving gear to the output shaft so it can transmit power to this shaft, and,
2. The collar ensures that the gear has the same speed as that of the output shaft.
Once the collar is connected to the first gear, the car is now in gear. To run the vehicle, press down the gas to put some RPM to the engine, then slowly depress the clutch by taking your foot off on it. The vehicle will begin to move forward.
If you want to go faster, you need to go to the second gear. Doing this, you must press the clutch pedal and shift the gearshift into the second gear.
For the rest of the 5 gears (if you have a 5-speed car), simply repeat the process of pressing and depressing the clutch pedal while one of your hands is controlling the gearshift.
To make a reverse maneuver, you have to stop the car to be able to reverse the gear. Unlike the first to fifth gears, the reverse gear is not constantly enmeshed with a gear on the countershaft.
Fg.4: Manual-Transmission
Fig. 5: A manual transmission diagram - Via: gfycat.com
Watch this video to know clearly how a manual transmission works:
Conclusion
Did you find this discussion interesting?
Even though an automatic transmission car is faster than a manual transmission but it gives drivers the full control over gears and when to shift and don’t cost as much.
Now you know how a manual transmission works, you will appreciate the fact that this transmission system is more engaging for the driver like you.
Please send your comments on the comment box below if you have something to say and share this article if you liked it.
