What Is Manual Transmission System? Its Parts and How It Works

A manual transmission is the oldest transmission used in automobiles to date. It uses a driver-operated clutch for engagement and disengagement via the foot pedal. Additionally, a hand lever and a hand-operated gear selector are both capable of doing it. This regulates torque transfer from the engine to the transmission.

In this reading, we’ll explore what a manual transmission is, its diagram, types, parts, and how it works.

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What is a Manual Transmission?

A manual transmission (MT) is a multi-speed motor vehicle transmission system that necessitates the driver to manually select the gears by operating a gear stick and clutch (which is typically a foot pedal for automobiles or a hand lever for motorcycles).

A manual transmission is essentially a mechanism that allows the driver to select from a variety of gear ratios to operate the vehicle. Lower gear ratios provide greater torque but lower speed, while higher gear ratios provide greater speed but less torque. A “six-speed” manual transmission boasts six forward gear ratios, as different gear ratios are frequently referred to as “speeds.”

The gearbox system is conventionally designed with a 5- or 6-speed manual transmission. It is standard in a modern base vehicle. The 5-speed types are common on commercial vehicles and lower-end vehicles. Higher-end vehicles like luxury and sports cars feature the 6-speed transmission for the base model. There are also other transmission options available.

Manual Transmission Diagram

Types of Manual Transmission

Below are the types of manual transmissions:

Sliding-gear Transmission

These types of manual transmissions are known as unsynchronized transmissions. It was invented in the late 19^th century, which is why it is found on older models of cars. When staying stationary when the transmission is neutral. In the transmission case, the main drive gear and cluster gear keep moving.

The clutch pedal must be pressed in order to free the shifter handle. The shifter handles change the position of the shift linkage and forks and slide a gear to the main shaft. The clutch is released once the gears have meshed.

Constant-Mesh Transmission

These types of transmission are known as synchronized transmission. The drive gear, cluster gear, and main shaft gears are in constant motion. This happens because the gears freely spin around the main shaft. Sliding gear transmissions are used to lock gears in place.

A dog clutch also helps to lock these gears in place when needed. The teeth on the dog clutch and main shaft gears lock onto each other and hold the gear stationary. This occurs as the shift linkage moves. The synchronizers are used in this transmission to prevent clashing or grinding while changing gears.

Preselector Manual Transmission

This manual transmission system was also developed before the invention of automatic transmission. It is known as the Wilson preselector, introduced in 1930. The transmission uses a planetary gear system to preselect the gear ratio. A small lever on the steering column is used. Drivers shift gears by pressing down the foot pedal, which notifies one of the preset gears. The previous gear disengaged immediately after the new gear engaged.

Parts of the Manual Transmission

Below are parts of manual transmission and their functions:

A clutch disc: allows the torque to be transmitted from the engine to the manual transmission system. This disc works when the clutch pedal is pressed.
The clutch pedal: is a manual transmission part that is operated hydraulically. When manually pressed, it controls the clutch disc.
Synchronizers: synchronizers allow the engagement between the collar and the gear. It makes the speed synchronized. The speed could end up being different but it prevents that from happening.
Flywheel: The flywheel is one of the major parts in manual transmission that sends torque from the engine to the clutch disc.
Gears: gears in the transmission are of different sizes, big and small. The big gears generate extra torque to slow down the speed of the vehicle. Smaller gears generate less torque, making the vehicle move faster.
Selector fork: a gear that allows the collars to move on the output shaft.
Stick shift: this manual transmission part is used for applying the gear by hand. It is connected to the gearbox.
Collar: collars are used to lock the selected gear in place and allow the torque to pass to the output shaft.

How Manual Transmission Works

The workings of this transmission system contain a set of gears along with a pair of shafts, which are the input and output shafts. The gears on the first shaft engage with those on the other shaft. The ratio between the selected gear on the input shaft and the gear engaged on the output shaft determines the overall gear ratio for that gear.

Gears are engaged in a manual transmission system by moving the shift lever. The linkages that regulate the movement of the gears along the input shaft perform the engagement. Cars with four gears or speeds have two linkages and cars with five or six speeds use three linkages. This linkage changes by moving the shift lever left and right.

The clutch plays an important role in the working of the manual transmission as disconnects the engine from the input shaft of the transmission when pressed. It frees the gears on the input shaft, causing it to easily move as the engine sends torque through the input shaft. This caused the engagement. The clutch is said to be disconnected when the clutch lever is not pressed.

Once the clutch disconnects the power from the engine to the transmission, the driver easily selects the gear and releases the clutch. Releasing the clutch allowed engine power to be reengaged to the input shaft, which makes the car move at the selected gear ratio.

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