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How does automatic transmission clutch work?

The automatic transmission clutch, how does it work and how do you know what is starting to fail?

The automatic transmission system is one of the most complex by ensuring that the engine´s force and power reach the wheels, with the minimum effort for the driver. The clutch is one of the components that make this possible. Below we will tell you what the clutch is in an automatic transmission, how it works, its estimated useful life, and which are the signs that could mean a failure is occurring. 

What is an automatic transmission clutch?

The clutch is the one that transmits power from the engine straight to the gearbox. When talking about automatic transmission clutches, the driver does not need to operate a pedal to transmit movement to the drive wheels and make a gear change, since the engagement and disengagement maneuvers are done autonomously. 

In an automatic transmission there are four clutches. As they turn on and off, they engage and disengage other gears to convert the energy into the drive that will start the vehicle. In addition, the clutch will allow shifting from one gear to another without the driver manually making the change.

A brief, how automatic transmission works? 

By now, you know that the main difference between a vehicle with an automatic transmission and a manual is that there is no clutch pedal to activate the gear shift. And the reason why the automatic system can work autonomously is because of its operation, which follows this mechanism: 

The planetary gear set is the main component of the automatic transmission. They have two inputs and one output. The two inputs are connected to the sun gear and ring gears, while the rotation of the output is done on the planet carrier.

When speeds are applied to the different inputs, the ring gear remains stationary and the sun gear rotates, causing the carrier and ring gear to rotate. When the sprocket rotates in the opposite direction, a reverse gear occurs.The mechanism of automatic transmission in general is to transmit different rotational speeds between the ring gear and the sun gear and the whole mechanism will be moving as a single unit.

How does the clutch in your car transmission work?

Between the input and output shafts of the planetary gear set there is not a direct connection, but an intermediate one through a shaft and two clutch packs to transmit the power of the motor. When the clutch blades are pressed together, the hub is pinched in the gearbox. 

The first clutch pack connects to the input shaft and will rotate the sun gear. And the second connects with the output shaft, which will make the ring gear stand still. 

Some automatic transmissions have two sets of planetary gears that will rotate at the same time at input shaft speed. In these, the ring gear connected to the output shaft will also rotate, thereby increasing the output speed. 

To actuate the clutch, the fluid pump is required, which works with the torque converter, activating the brakes and clutches with the pressure of the pump, as well as the set of planetary gears. 

Another component called the rotor rotates in the pump casing, creating chambers that cause volume change and compression of the gears. Hydraulic signals are sent through the clutches and band brakes. 

How long automatic clutch last?

Automatic transmission clutches are designed to last between 30,000 and 100,000 miles. In other words, they have a very long useful life that can be extended even more depending on how you drive, the way you reverse gears, how you stop the vehicle, the amount of weight that the transmission regularly tolerates and the maintenance periods to the general transmission system. 

In addition, taking care of the transmission fluid is part of the maintenance that should not be forgotten.

Signs you have a failing automatic clutch

The following signs could be telling you an automatic transmission clutch failure may be present: 

Excessive transmission noise

If you notice that the vehicle is making a lot of noise as if you are accelerating, but it is not going any faster, it could be a slipping clutch. Meaning that the clutch discs do not engage correctly with the gears, which is why you might be hearing an acceleration noise, but the corresponding mechanical propulsion is not given. 

Running delay

If it has ever happened to you that you stop at a traffic light and when pressing on the accelerator your vehicle does not move, the reason is probably a damaged clutch that causes a delay in driving and changing speed. 

Dark or burnt transmission fluid

There are many reasons why ATF looks dark or has a burning smell. One of them is a damaged clutch. In this case, in addition to the appearance and odor, there could be a dark, sludge-like material within the fluid. 

Find automatic transmission parts at Sun Transmissions

We hope that the information given on this blog will help you learn more about the automatic transmission clutch.  At Sun Transmissions you will find this and other automatic transmission parts to repair your vehicle. Browse our website to purchase the ones you need, and if you would like more information, write to us through the online chat where our advisors are ready to assist you.

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