Picture this: You have a water hose in your hand and there is a fan standing in front of you. When you spray water on the blades, they will begin to spin. If you play with it a little more and change the force at which the water is hitting the blades and the angle at which you are spraying, the blades will speed up or slow down. The Pump of the torque converter represents you holding the water hose and the turbine of the converter represents the fan.

The fluid then enters the blades of the “Turbine”, which is connected to the transmission via the input shaft. The turbine/input shaft causes the transmission to spin the planetary that connects the output shaft of the transmission, which is connected to the driveshaft, then rear-end, the axles, which basically moves your car. You can see in the graphic below that the blades of the turbine are curved. This means 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.

In order to change the direction of a moving object, you must apply a greater force to that object. It doesn't matter if the object is a car or a drop of fluid. And whatever applies the force that causes the object to turn must also feel that force, but in the opposite direction. So 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) is 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” sends the fluid returning from the Turbine to the Pump.This improves the efficiency of the torque converter.

The “Stator” resides in the very center of the torque converter. It is the “brain” of the 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.

The “Stator” has a very aggressive blade design that almost completely reverses the direction of the fluid. A one-way clutch called a “sprag” (inside the stator) connects the stator to a fixed shaft in the transmission called a “Stator Support.” Because of this arrangement, the stator cannot spin with the fluid -- it can spin only in the opposite direction, forcing the fluid to change direction as it hits the stator blades.

Something a little bit tricky happens when the car gets moving. There is a point & time at which both the pump and the turbine are spinning at almost the same speed (the pump always spins slightly faster). At this point, the fluid returns from the turbine, entering the pump already moving in the same direction as the pump, so the stator is not needed. It’s one-way clutch or sprag allows it to “freewheel.”

Even though the turbine changes the direction of the fluid and flings it out the back, the fluid still ends up moving in the direction that the turbine is spinning because the turbine is

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spinning faster in one direction than the fluid is being pumped in the other direction. The fluid is being flung out the back in one direction, but not as fast as it was going to start with in the other direction.

At these speeds, the fluid actually strikes the backsides of the stator blades, causing the stator to freewheel on its one-way clutch so it doesn't hinder the fluid moving through it.