What is a 6AT Transmission?

[HarmonyAnn]

6AT transmission refers to a car's transmission having 6 gears. Generally speaking, the more gears there are, the more detailed the division, which greatly improves the car's fuel economy. The meaning of 6AT is a 6-speed automatic transmission. Some automatic transmissions have a manual mode, and this type of transmission is also called a semi-automatic transmission. AT is a torque converter transmission. Automatic transmissions also include AMT, DCT, and CVT. The AT transmission is the most mature and widely used transmission. DCT is also called a dual-clutch transmission. The structure of this transmission is similar to that of a manual transmission, with two sets of clutches. These two sets of clutches respectively control odd and even gears. The dual-clutch transmission has fast shifting speed, high transmission efficiency, and is very suitable for use with some small-displacement turbocharged engines. AMT is the earliest automatic transmission. The structure of this transmission is the same as that of a manual transmission, except that it has a set of control mechanisms that can control the clutch and gears. CVT transmissions are often used in some domestic or Japanese cars. This type of transmission is small in size, light in weight, and has a low cost. Most cars equipped with CVT transmissions are quite fuel-efficient. CVT transmissions have no jerking, and the smoothness of this transmission is very good. The jerking of AT transmissions during shifting is also quite small. Dual-clutch transmissions have noticeable jerking during low-speed shifting. AMT transmissions have very large jerking, and this type of transmission has been phased out. The research and manufacturing costs of AT transmissions are generally very high, and AT transmissions are often used in some high-end cars. A semi-automatic transmission combines the manual shifting and automatic shifting of a car. This transmission combines the advantages of automatic and manual transmissions, minimizing the power loss of the shifting system. Manual transmissions allow the driver to freely adjust gears and RPM according to their subjective will. The manual mode of a semi-automatic transmission is different from that of a purely manual car. Although it has a clutch device in its structure, it requires the driver to operate it, which means an automatic clutch. When using the manual mode in a semi-automatic car, you only need to switch to manual mode and adjust the gears up or down as the speed changes. If the speed does not match the corresponding gear, the gear will automatically shift down; if the speed is higher than the current gear, you need to manually shift up. Working principle: In terms of structure, a semi-automatic transmission mainly consists of an ordinary gearbox (the same as a manual transmission), an electronically controlled clutch, an automatic shifting mechanism, and an electronic control part. The function of the electronically controlled clutch is to automatically separate, engage, or "slip" the clutch as needed. During operation, the transmission ECU controls a stepper motor to push the clutch fork, separating or engaging the clutch. The function of the automatic shifting mechanism is to automatically engage the corresponding gear as needed. Generally, two stepper motors are set, both controlled by the transmission ECU. The gear lever setting is similar to that of an ordinary automatic transmission, with no clutch pedal. The operation of this transmission actually uses the automatic control part to simulate manual shifting. During normal driving, it is no different from a hydraulic automatic transmission, except that when stopped, the clutch is separated. Therefore, if you stop on a slope, you must step on the brake, otherwise the car will roll. If you use the manual mode, it will feel like driving a manual car, with very direct power delivery, eliminating the need to step on the clutch, and you don't need to shift gears one by one—you can skip gears when shifting up or down.

[StCorey]

I've always thought the 6AT transmission is a pretty cool piece of technology. Simply put, it's an automatic transmission in cars with 6 forward gears. As someone who enjoys studying mechanics, I know it uses a torque converter and planetary gear sets to automatically shift gears, unlike manual transmissions that require clutch pedal operation. This design makes driving smoother, especially in traffic jams where it saves effort, while also improving fuel efficiency compared to older 4AT models. However, its more complex structure requires attention to fluid changes during maintenance, with inspections recommended every tens of thousands of kilometers to prevent minor issues like gearshift jerks. If you're passionate about automotive innovation, the 6AT was a major trend a decade ago, representing significant progress in automatic transmission technology.