How Does a Torque Converter Work?

By Mister Transmission

Torque converters are sealed units; their innards rarely see the light of day, and when they do, they’re still pretty hard to figure out!

Imagine you have two fans facing each other. Turn one fan on, and it will blow air over the blades of the second fan, causing it to spin. But if you hold the second fan still, the first fan will keep right on spinning.

That’s exactly how a torque converter works. One “fan,” called the impeller, is connected to the engine (together with the front cover, it forms the outer shell of the converter). The other fan, the turbine, is connected to the transmission input shaft. Unless the transmission is in neutral or park, any motion of the turbine will move the vehicle.

Instead of using air, the torque converter uses a liquid medium, which cannot be compressed – oil, otherwise known as transmission fluid. Automatic transmission cars use a torque converter. This article will discuss why automatic transmission cars need a torque converter and how a torque converter works.

The torque converter in an automatic transmission serves the same purpose as the clutch in a manual transmission.

The engine needs to be connected to the rear wheels so the vehicle will move, and disconnected so the engine can continue to run when the vehicle is stopped. One way to do this is to use a device that physically connects and disconnects the engine and the transmission – a clutch. Another method is to use some type of fluid coupling, such as a torque converter, which is located between the engine and the transmission.

There are three components inside the very strong housing of the torque converter which work together to transmit power to the transmission:

  • Pump
  • Turbine
  • Stator

The pump inside a torque converter is a type of centrifugal pump. As it spins, fluid is flung to the outside, much as the spin cycle of a washing machine flings water and clothes to the outside of the wash tub. As fluid is flung to the outside, a vacuum is created that draws more fluid in at the center.

The fluid then enters the blades of the turbine, which is connected to the transmission (the spline in the middle is where it connects to the transmission.) The turbine causes the transmission to spin, which basically moves your car. The blades of the turbine are curved so that the fluid, which enters the turbine from the outside, has to change direction before it exits the center of the turbine. It is this directional change that causes the turbine to spin.

As the turbine causes the fluid to change direction, the fluid causes the turbine to spin.

The fluid exits the turbine at the center, moving in a different direction than when it entered. The fluid exits the turbine moving opposite the direction that the pump (and engine) are turning. If the fluid were allowed to hit the pump, it would slow the engine down, wasting power. This is why a torque converter has a stator.

The stator resides in the very center of the torque converter. Its job is to redirect the fluid returning from the turbine before it hits the pump again. This dramatically increases the efficiency of the torque converter.

In brief, the torque converter is a type of fluid coupling, which allows the engine to spin somewhat independently of the transmission. It is responsible for pressurizing automatic transmission fluid, a pressurization that supplies the force necessary to shift transmission gears.

A worn or dysfunctional torque converter can prevent transmission fluid from being properly pressurized, which in turn negatively impacts transmission gear function and operation. A systematic checkup by a professional is the best way to isolate the cause of the operating problems and recommend the most effective solution.

If properly tuned, this complex device can have a tremendous impact on your vehicle’s performance, economy and durability, and turn your automatic into a powerhouse!

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Albert Wilton
Good and friendly and reliable people and they work hard to get your vehicle doneService: Transmission
Date: July 25, 2021
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Thank you, Mister Transmission! After...
Christy McMurray
Thank you, Mister Transmission! After taking my vehicle to the dealership where I bought it, and paying $150 for them to tell me what I already told them was wrong, the Dealer gave me a quote of $6,500 to replace my 9 year old transmission with a factory rebuilt one, because it couldn't be fixed or rebuilt by them. Thankfully I called Mister Transmission and Chris knew exactly what the issue was, how to fix it, and it only cost me $385 for everything and it was fixed in a day. I am so grateful that Chris and Dawn run an honest operation and provide genuinely great service. Thanks again!
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Cambridge Mister Transmission was awesome....
Sarah MacArthur
Cambridge Mister Transmission was awesome. We ended up having a small issue but they still took the time to show me where on my vehicle the problems were and fully explain the possible issues. They were prompt in getting back to me the following day and I had my vehicle back in no time. Chris and Nick were amazing and the office is so clean and pleasant. Great customer service!
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Great service , friendly and very knowledgeable.Excellent work
Date: July 23, 2021
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Mazda 3 AT light came...
Chris Elmquist
Mazda 3 AT light came on one with some bad noises and clunking. Dealer said need a new transmission for only $4400. Took it to this and a quick check they determined it needed new TCM which is very common on the mazdas. They took care of it and even did a bunch of extra work fixing a wiring harness all for the cost of the TCM . cannot say enough about how we were treated by Chris and Dawn. Would recommend them. FIRST CLASS!!!!!
Date: July 23, 2021
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Workers are very nice and...
Ely Bolivar
Workers are very nice and explain thing clearly. Also they have an option to finance your repairs.
Date: July 22, 2021
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They assessed the problem quickly,...
Colleen H
They assessed the problem quickly, quoted a good price, provided fast service, in a no-pressure, friendly manner. I've been telling everybodyService: Transmission
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I took my differentials down...
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I took my differentials down to get rebuilt and Steve was very professional and the total was 200 bucks cheaper than the quoted price and there was a few things during the whole process that didn’t go as planned as I had brought all the bearings parts and some bearings were the wrong ones and I had brought 4.88s to put in end they would not work and before continuing with anything Steve would call and double check to let you know what needs to be done and get the ok from me first before they would continue overall amazing place Steve and the guys were awesome and the work was done perfect and the diffs have never been more smooth highly recommend.
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Thank you Kyle and the Mr. Transmission team for very professional and friendly customer service and repair. I definitelly recommend their services.Service: Transmission
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