Gearbox AMT (automated manual transmission): features, testimonials

Recently, in cars of foreign production, there is an automated mechanical transmission. This is not a classical mechanics and not a well-known automaton. This is something average. What is an AMT box? Reviews and the device of an automated transmission - later in our article.

Characteristic

This unit is a mechanical transmission. But the switching of speeds here occurs in an automatic mode. The choice of the required transmission is made by the electronic control unit. The computer responds to the sensor signals and generates a reverse pulse. As a result, the car moves in the most optimal speed mode. This transmission (AMT) combines the economy of mechanics and the convenience of automatic transmission. Now such checkpoints are installed on cars "Skoda", "Audi" and "Volkswagen".

About construction

What does the AMT gearbox consist of? This transmission includes several components:

• Drive and clutch discs.
• Shift lever.
• Electronic control system.

Any robot uses a double friction clutch. On a conventional mechanic, one disc is used. This design allows you to quickly switch gears to AMT. "Lada Vesta", which began to install robotic boxes, much faster than its analog on the mechanics. And this is despite the fact that the clutch pedal in AMT is not as such. But not only concern Volkswagen-Audi and AvtoVAZ use such a box. The robot AMT has long been installed on the German "Mercedes". Here we use the 7-JITRONIC. But German engineers took as their basis an automatic box, replacing the torque converter with friction clutch. Also, the robotic AMT transmission is used on BMW cars. It is a six-speed transmission with electrohydraulic drive. A 5-speed transmission is often used by Volkswagen-Audi.

Types of clutches

There are several types of clutches in the AMT box:

• Electric.
• Hydraulic.

In the first case, electric motors are used. Such a drive has a lower response speed. Gear shifts are three to four times slower than those with a hydraulic drive. The switching time is 0.3 to 0.5 seconds. But still faster than automatic transmission. As for the hydraulic drive, special cylinders are used here. They are controlled by a solenoid valve. Such a design is more complicated, but at the same time it has a fast response. The time for shifting at the gearbox with hydraulic drive is about 0.1 seconds. This gearbox AMT is installed on a predominantly expensive car. Electric equip all other machines of medium and budget class. Among them - Skoda Octavia, Superb, Scout, Volkswagen Golf, Audi RS and others.

About Transmission Efficiency

According to manufacturers, the robotic box is one of the most technologically efficient in terms of efficiency. It is about 97 percent. On the automatic transmission, the efficiency is 90 percent. As for mechanics, this figure is almost the same as in the robot - 98 percent. Consequently, such machines are more dynamic.

Benefits

The main advantages of an automated gearbox:

• Low fuel consumption. The machine on the "robot" spends almost as much as on the mechanic.
• A small amount of oil. In this box it is necessary to fill up to 4 liters of liquid. This is two times less than on a similar automatic transmission or variator.
• High clutch life. Since the switching process is controlled by electronics, not by the driver, the risk of burning the clutch is near zero (unless you intentionally press the accelerator and the brake simultaneously).
• The presence of semi-automatic mode. At any time, the driver can switch to manual mode and choose the moment when to switch to an increased or lowered gear.

Also, drivers note a high switching speed, even in automatic mode. And all thanks to the use of multi-plate clutch. When the machine is moving in the first gear, the second disc is already in mesh with the next gear. And so on until you switch to the final one. If you are driving at the maximum possible, sixth or seventh speed, the drive will automatically be meshed with a reduced gear. Overclocking up to a hundred of these machines is comparable with mechanics. The box is not "tupit" when overclocked, and this is a big plus, note the reviews of car owners. The gear shift is made without a break in power and dynamics.

Disadvantages of the transmission

The reviews point out the impossibility of flashing the checkpoint to another mode. Also, when driving in a traffic jam, car owners are very hot on the clutch. To save the box from wear, you have to switch to the "Tiptronic" mode. You can not often travel with a trailer. The clutch resource will be much less under this load. In addition, a big disadvantage is the cost of servicing the checkpoint. Not all boxes fall under the warranty case. It is necessary to regularly change the clutch disc. And since there are two of them in AMT, the price of service substantially increases. In 150 thousand it is necessary to change friction clutches. Also, car owners are faced with the wear of the bearings of the input shaft. Such a breakdown is accompanied by a characteristic noise in the area of the checkpoint. With increasing engine speed, it increases. This fault occurs due to the presence of metal chips in the mechatronics unit. If the failure is not rectified in time, this will lead to a rapid deterioration of the clutch discs. What is most sad, new details on AMT are not sold. All that can be done is to get a more or less "live" box on the analysis and remove the necessary details from it. On many cars of the Volkswagen brand, this transmission jerked, suddenly releasing the clutch. The reason was mixing two types of oils, which are used in AMT. The reason for this is a poor seal on the mechatronic block. So, about 1 million cars for the replacement of oil were recalled.

About oil change

The manufacturer recommends changing the transmission fluid at least once every 60,000 kilometers. The cost of a new oil for AMT is 4 thousand rubles. Also it is necessary to buy a new filter for 500 rubles. Oil is replaced by a specialized service and costs about 2200 rubles.

Operating modes of the automated box

During the movement, the driver can set the shift lever in automatic or semi-automatic mode. In the first case the transmission operates, relying on the readings of the sensors and the pulses of the electronic control unit. As for the semi-automatic mode, the "Tiptronic" is used here, which can be found on the "Mercedes" cars with their automatic transmissions. The shift lever has a plus or minus switch. On some machines set podolevye petals. Thus, the AMT transmission no longer accepts signals from the sensors, but can be instructed by the driver. Some call this mode sporty. The switching speed here is the same as in the automatic mode. But here you can choose the speed at which the reduced or increased speed will turn on.

Conclusion

So, we found out what a robotic gearbox is. As you can see, it combines the economy of mechanics and the comfort of the machine. But in terms of service this transmission is one of the most expensive. Often the cost of repairs reaches a mark of 1-1,3 thousand euros. If the mileage of the car is less than 150 thousand (or five years), the repair is taken by the dealer himself. But what happens when the car "flies" off the guarantee? All problems and maintenance costs are borne by the car owner. Knowing the problems with AMT, such cars are difficult to sell on the secondary market.