Essential Guide to Manual Transmissions

The manual transmission which is also known as the gearbox is a standard transmission. It is also called a stick shift or simply stick as well as the gearbox. The transmission system is used in motor vehicle applications.

A manual transmission is the oldest transmission used in automobile till date. It uses a driver-operated clutch for engagement and disengagement via the foot pedal. It can also be done using hand lever along with a gear selector which is operated by hands. This regulates torque transfer from the engine to the transmission.

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The gearbox system is conventionally designed with 5- or 6-speed manual transmission. It is standard in a modern base modern 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 choices of transmission available.

Below is the diagram of manual transmission:

Types of Manual Transmission 

below are the types of manual transmission:

Sliding-gear transmission:

These types of manual transmission are known as unsynchronized transmission. It was invented in the late 19^th century which is why they are found on older model 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 press in order to free to shifter handle. Shifter handles changes the position of the shift linkage and forks and slides a gear to a main-shaft.  The clutch is released once the gears meshed.

Constant-Mesh Transmission:

These types of transmission are known as synchronized transmission. The drive gear, cluster gear and main shaft gears in constant motion. this happens because the gears freely spin around the main shaft.

Sliding gear transmission is used to lock gears in place. A dog clutch also helps to lock these gears in place when needed. 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.

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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 gear ratio. A small lever on the steering column is used. Drivers shift gears by pressing down the foot pedal that notifies one of the preselected gears.

The previous gear disengaged immediately the new gear engages.

Parts of the manual transmission system and their functions

Below are parts of manual transmission and their functions:

• 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.
• Clutch pedal: is a manual transmission part that is operated hydraulically. it controls the clutch disc when pressed by foot.
• Synchronizers: synchronizers allow the engagement between the collar and the gear. It makes the speed to be 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 send torque from the engine to the clutch disc.
• Gears: gears in the transmission is of different sizes of 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 to move faster.
• Selector fork: is a gear that allows the collars to move on the output shaft.
• Stick shift: this manual transmission part is used for applying the gear via hand. It is connected to the gearbox.
• Collar: collars are used to lock the selected gear in place and allow the torque to past to the output shaft.

How manual transmission works

The working of  this transmission system contains a set of gears along with a pair of shafts which is the input and output shafts. The gear on the first shaft engages 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 manual transmission system by moving the shift lever. The engagement is done by the linkages that control the movement of the gears along the input shaft. Cars with four gears or speed have two linkages and cars with five or six speeds has uses three linkages. This linkages changes by moving the shift lever left and right.

Clutch plays an important role in the working of the manual transmission as disconnect 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 is sending torque through the input shaft. This caused the engagement. The clutch is said to be disconnected when the clutch lever is not press. Once the clutch disconnects the power from the engine to the transmission, the driver easily selects the gear and release the clutch. Releasing the clutch allowed engine power to be reengaged to the input shaft which makes the car to move at the selected gear ratio.

The video below contains how the manual transmission system works:

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