If you read some online advice, you may think there is no need to service an automatic transmission regularly. You may be led to believe that these systems are designed to work under high pressure for great periods of time, and you may only need to change the fluid occasionally. Yet in truth, there is more to it, and you will need to service the system properly if you want it to last as long as possible. What is the significant risk here, and what should you do?
How It Works
The transmission system in a car fitted with a manual gearbox is relatively simple compared to the automatic alternative. Much of the "action" is mechanical, as the driver separates the engine from the transmission using a foot-activated clutch. Inside the automatic transmission, however, is a special gadget known as a torque converter. This will also separate the engine from the drive, but it will use hydraulic pressure to do so.
Inside the torque converter is a powerful turbine that will spin at the same speed as the engine, building pressure. Hydraulic fluid is then forced through a chamber and spins outward towards the side of the casing. Most of this fluid will then be pumped back to repeat the action but, over time, tiny particles of dirt or metal will stick to the outside wall, which is where the problem lies.
When the vehicle is stationary, and the system has time to cool down, those particles of dirt can harden against the casing's inner wall. Over time, a layer of dirt will accumulate until tiny pieces start to break off. These pieces can then find their way into vulnerable parts of the system, and this could cause inefficiency, damage, or even failure. The transmission could start to slip, and you may notice that the vehicle is far less responsive.
Of course, you can get rid of dirty fluid when you change the engine and transmission oil, but you will not be able to get rid of that accumulation of dirt. You will need to perform a full automatic transmission service using specialised equipment and will need to take the vehicle to an experienced mechanic to do so.
The mechanic will connect a machine that is designed to flush out the entire automatic transmission system, including the torque converter. It will use chemicals to clean the inside wall of transmission, softening the dirt and sucking it out at the same time.