Transmission, as one of the main components of the truck, is the core of the whole truck transmission system; in the whole truck system, the engine is responsible for providing power, while the transmission is responsible for turning the power coming from the engine. Transmission is an indispensable and important part of the whole truck. If it is said that the engine is the heart of the truck, then the transmission is the soul of the truck, and the importance of the transmission can be seen from this statement.


The transmission consists of input shaft clutch output shaft clutch input shaft, output shaft, gear, locking clutch set drive shaft, locking clutch set toggle shaft, reverse gear shift shaft, locking clutch set return spring, etc.


A gearbox is a gearbox that changes the transmission ratio and direction of movement. It is located between the clutch and the central drive. The main function is: in the case of engine speed and torque remaining unchanged, change the driving force and driving speed of the truck (shift); so that the truck can drive backward (shift); the engine can stop without stalling (neutral).

Forward gear stage: Both input shaft clutch and output shaft clutch are combined, the first sliding gear of the output shaft engages in the first active gear of the input shaft, and the input shaft drives the front section of the output shaft to rotate, and the front section of output shaft drives the rear section of the output shaft to rotate, and the engine power can be output to the wheels smoothly.

shift phase: When the truck is in the shift state, the driver separates the input shaft clutch transmission input shaft loses power; the wheel becomes the active part, the power will be reverse input to the transmission, at this time, due to the characteristics of the output shaft clutch one-way drive, reverse drive output shaft clutch is in the separated state. At this time, the transmission input shaft is in a state of loss of drive in the front section of the transmission output shaft, and the output shaft sliding gear realizes the engagement with the second active gear of the input shaft on the input shaft by pulling the fork to complete the operation of smooth gear shift.

Reverse gear stage: When reversing, the input shaft clutch is separated, the reverse sliding gear engages with the reverse intermediate gear through the fork, and the reverse intermediate gear engages with the reverse active gear of the input shaft. At the same time, the reverse gear shifting shaft is linked with the locking clutch sleeve toggle shaft, so that the locking clutch sleeve locks the front section of the output shaft and the rear section of the output shaft together through the spline inside the locking clutch sleeve inside it, and realizes the rotation of the rear section of the output shaft.

braking stage: truck downhill, the need for engine braking, the driver alone to manipulate the locking clutch sleeve, lock the front section of the output shaft and the rear section of the output shaft, and then hook up a forward gear, the truck has the engine braking function.


Manual mechanical transmission (MT)

The so-called manual gearbox generally means that the gearbox shift is realized by manual means, and the clutch is also realized by manual operation at the moment of gear shift. Manually move the shift lever (grip) to change the meshing position of the gears in the transmission, and combine the gears of different sizes with the power take-off shaft to change the torque and speed of the drive wheel, so as to achieve the purpose of shifting. Compared to other types of transmissions, manual mechanical transmission operation is quite physically demanding for the driver. This is the basis of transmission together and is the most used type of transmission in China at present.

Automatic Transmission (AT)

It is generally rarely used in domestic trucks, only in some special trucks such as firefighting and oilfield equipment; AT is especially characteristic of its own products, with the presence of torque converter, fuel consumption has always been a problem, so domestic trucks are generally rarely equipped.

Mechanical automatic transmission (AMT)

The so-called mechanical automatic transmission (AMT) is essentially a mechanical transmission with a set of automatic shift actuators on top of it. AMT transmission combines the advantages of AT and MT transmission, which ensures low fuel consumption and convenience of driving at the same time.

  1. Comparison

Manual transmission:


A. High efficiency, reliable work, relatively simple structure.

B. direct and rapid gear shifting, so fuel-efficient, sporty and fun to drive.


A.Poor adaptability, unstable work, short service life.

B.high requirements for driving skills, increasing the driver’s labor intensity.

Automatic transmission.


A. Easy and simple operation, reducing driving fatigue.

B. The use of hydraulic transmission, gear changes slowly, can maintain the smoothness of driving.

C. Relatively small failure rate, improves the service life of the engine and driveline.


A. Automatic transmission because of the production of precision, is relatively expensive.

B. Poor drafting brake effect, fuel consumption, long-term driving is easy to lose the driving pleasure.


At present, AMT models are definitely one of the hottest areas in the heavy truck market. Behind the hot sales of AMT heavy trucks, the competition in the field of heavy truck AMT gearboxes is also surging. However, competition in the AMT era is not limited to independent gearbox suppliers. Many domestic heavy truck OEMs, including Sinotruk, are also deeply involved in the field of AMT gearboxes.

Sinotruk S-AMT 16-speed gearbox is the first mature application of a 16-speed AMT gearbox in the domestic heavy truck industry, and the transmission efficiency is as high as 99.7%.

This product can realize free switching between automatic and manual modes, and has functions such as creeping, sliding, kickdown, and ramp perception, freeing the right hand of the truck driver, reducing fatigue and improving driving comfort. In addition, the S-AMT 16-speed gearbox can intelligently match different gears according to the actual truck weight, slope and other working conditions, and easily adapt to various complex working conditions to obtain the best power performance and fuel-saving effect.

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