Manual transmission parts and function

The transmission functions to change the speed and torsional moment the engine produces to transmit to the wheels. Apart from that, the transmission also has several important functions for the vehicle. At least, there are four transmission functions that we know about, namely:

It forwards the power and engine speed from the clutch to the propeller shaft.
Change the moment the engine produces according to driver needs.
Allows the vehicle to go backward.
Allows the engine to start in neutral.

As a part of the power train system, the shape and model of the manual transmission can vary, especially if it is related to the drive system used in the vehicle.

For example, manual transmission for a front-drive car will differ in shape from a manual transmission used in a rear-drive car. But generally, all the manual transmission components are mostly the same, which distinguishes only the location and shape. Pay attention to the image of manual transmission part names below.

manual transmission diagram, part names and function

So what are the manual transmission parts and functions? The following article will explain the various manual transmission part names and their functions.

1. Input Shaft

The input shaft is parts of a transmission associated with the clutch. The input shaft is the initial shaft where the engine power flows from the clutch to the gears in the transmission. The function of the input shaft is to rotate the gear for the first time before it is transferred to the other gear positions in the transmission gearbox.

2. Transmission gears

The transmission gear is parts of a transmission arrangement of several gears that function to change the engine speed input into the transmission output. It results in changes in torque or speed that will leave the transmission according to the driver's needs.

3. Synchromesh gear

A synchromesh gear is an additional transmission components placed on each transmission gear (mostly on forward gears). This synchromesh gear prevents gear changes before the rotation between the two teeth of gears that are connected is at the same line. That way, synchromesh can make it easier to shift gears in fast rotation between one gear and another.

4. Shift fork

The shift fork functions to move the sliding gears and operate the transmission gear system from its shaft. Shifting gears from one gear to another becomes easy to do.

5. Shift linkage

The shift linkage links the gear lever and the shift fork. In this shift linkage, an interlock mechanism prevents the shift fork from moving by itself. This component is responsible for moving the shift fork so that the gear shift fork can proceed to connect the transmission gears.

6. Gear shift lever

This transmission/gear shift lever is a lever located in the car cabin that functions as a tool for the driver when shifting the transmission based on driving conditions. Usually, there is a gearshift diagram on the transmission lever to make it easier for the driver to know the position of the gear used.

7. Output shaft

Output Shaft is parts of a transmission that will continue the engine's rotational power out of the transmission to the propeller shaft. The output shaft is connected to the gear arrangement in the transmission from 1st gear to reverse gear. The function of this output shaft is to continue the rotation from the transmission to the propeller shaft.

8. Transmission bearings

The transmission bearing reduces the friction between the rotating components' surfaces, such as the input shaft, output shaft, and counter gear. Various forms of bearings are used in transmissions, generally using needle bearings, ball bearings, and tapered bearings.

9. Counter gear and shaft

This counter gear and the shaft is a connecting gear that will connect the engine speed from the input shaft to each of the acceleration gears. The function of the counter gear is to move the rotational power from the input shaft to the acceleration gears according to the gear selected by the driver. This counter gear is generally fused between the gear and the shaft and mounted on a transmission case.

10. Transmission case/ transmission body

The Transmission Case is used as a protection for the transmission components and functions as a holder for the transmission bearing along with its input and output shafts. Also, this transmission body is used as a place to accommodate transmission oil.

11. Extension housing

The extension housing is a connection from the transmission body with a conical shape at the end. There is an oil seal that prevents transmission oil leakage. This Extension Housing functions to protect the output shaft components that come out of the transmission body and as a place to mount the speedometer gear.

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12. Speedometer gear

The speedometer gear is connected to the vehicle speed measuring device on the dashboard panel, which measures the vehicle's speed while driving. This speedometer gear is generally installed right on the output shaft. This gear will be connected to the speedometer cable.

13. Transmission oil seal

A transmission oil seal is a seal component that prevents transmission oil leakage. Oil seals are usually installed on the transmission shaft, i.e., on the input and output shaft.

14. Control rod

The control rod is parts of a transmission that connects the shift lever with the rod end. It is also used to move the rod end.

15. Shift rod end

The shift rod end is located on the shift fork shaft, connects the control rod to the shift fork shaft, and moves the shift fork shaft when connecting the transmission gear.

16. Reverse gear

Reverse gear is a manual transmission components that functions to change the rotation of the output shaft. The car can move backward with this reverse gear when the gear lever is in the R (Reverse) position.

17. Clutch hub sleeve

The clutch hub sleeve is directly related to the hub sleeve. The clutch hub sleeve connects the main gear with the hub sleeve so that the rotational power from the acceleration gear can be directly forwarded to the main shaft/output shaft.

18. Hub sleeve

The hub sleeve is also connected to the main shaft right in the groove. When the single hub is connected, it can continue the rotation of the acceleration gear to the main shaft/output shaft. This hub sleeve functions as a lock for the acceleration gear adjustment. With this component, the output shaft can be adjusted to rotate or stop.

19. Shifting key (lock pin)

The shifting key (lock pin) is installed on the hub sleeve and functions to transmit the compressive force from the hub sleeve to the synchronizer ring. It makes that braking occurs on the tapered part of the acceleration gear.

20. Spring key

The spring key is installed on the inside of the sleeve hub. It functions to press the shifting key to keep it pressed against the clutch hub so that the shifting key can continue to lock the synchronizer ring.

21. Interlock system (gear locking mechanism)

The interlock system consists of a detten ball and a spring located on the shift fork shaft. In the shift fork shaft, we find grooves where the detten ball is pressed by the spring when the transmission is positioned into gear. This detent shift mechanism prevents the gear and fork from shifting back to neutral. Also, this system is used to assure the driver that the gears are fully engaged.