Okay, I'm no DIY mechanic, but I do possess a general knowledge about cars. When magazines, articles, etc. speak about characteristics of a torque converter, it sort of baffles me. What exactly is it that they're "feeling" when they drive off that they speak of?

I drive a m/t, so I understand the differences and all that jazz.

 

Fluid Couplings!

http://www.youtube.com/watch?v=leCEmJA0WsI

As far as the differences magazines talk about. They can tune it to "lock" at different rpms and different um... positiveness? They may set up a higher stall on a engine that makes it's power at higher rpm or for higher gear ratios.

 

Didn't watch the 12 min video on my phone, but will later on.

I don't know the exact details of how they work but got the basic idea of it.

With in the converter, there are two revolving plates that stand next to each other. There is one thats mechanically joined with the engine.
And the other, that is mechanically joined with the transmission. These plates have holes/channels/blades on them. When the engine turns, the plate on its side spins which spins the oil with in the torque converter. When that oil spins, it creates directional force that spins the other plate connected to the transmission. Keep in mine there is no direct connection between the motor and the Tranny. Which is the reason why you can idle with the car in gear and not have it stall on u.

 

Very interesting. I was always curious about this too.

 

It basically works how nspec mentioned with the device stapler posted.

A torque converter in a car is basically a link between the crankshaft of the engine and the input shaft of the the transmission. It is filled with fluid, and the movement of this fluid is what allows it to function. A torque converter is also very important as it allows a car equipped with an automatic transmission to come to a complete stop while still in gear without stalling. It also acts as a torque multiplier, which allows the car to take off in gear from standstill in a reasonable manner.

A torque converter is actually a fairly simplistic device. It's basically composed of a "pump" or "impeller" connected to the inside of the converter housing. A torque converter is attached to the engine's flexplate, so the pump is always working while the engine is running. The next is a turbine connected to the transmission's input shaft. The final component is a stator assembly, which redirects the flow of fluid between the pump and turbine.

A common analogy is to think of the pump and the turbine as two fans and the stator a device controlling airflow between them. One fan, the pump connected to the engine is always being driven, while the other fan, the turbine connected to the transmission can remain stopped independently. The stator, controlling the airflow, can not only cause the fan connected to the transmission to turn, and can also redirect to air causing it to stop, allowing the transmission to remain in gear while the car is stationary. Again, this is a very simplistic analogy.

I recently rebuilt a Ford automatic, but didn't take any pics of the internals. There is another I'll be starting eventually and can take some pics and detail the process if you like.

 

Thanks for asking this question. I just learned something.

 

We all learn so much when you take pictures and detail processes, so if it's not too much trouble, please do.

And great explanation, too

 

Im in to see some pics as well, Terry.

So what Im getting out of it is that its just a means of using fluid to take the torque from the motor and get it to the transmission?

 

Simply put, yes. Think of the fluid as a medium between the pump or impeller of the engine side and the turbine of the transmission side. As the engine side is always in constant rotation while running, a device is needed that allows a car remain in gear but not move. In a manual equipped automobile, the engine could not continue to rotate if the car was in gear and stationary. Under acceleration or movement, it's the fluid that allows the two sides to "engage". Again, I'm oversimplifying things, but you get the idea.

 

Read about this on HowStuffWorks, but it just made it more confusing. Thanks for the basic explanation, guys. Learned something great today.

How thick is the fluid used compared to engine oil?

Aren't fluid couplings also used in some AWD differentials? Or something similar?

 

It's transmission fluid. I've only dealt with Honda Z1 and DW-1, and they're a little thinner than 5W-20 engine oil.

 

OK, I learned how a Torque Converter works.



Now, what is meant by Torque Converter Lockup? And what is meant by "stalling" the Torque Converter?

 

My guess is that by design, there's always some slip present in the coupling, so the transmission never gets 100% of the engine's torque. A lockup is a system that directly connects the engine to the transmission via a more solid means than fluid, maybe some sort of clutch system? So the engine and the transmission's input shaft are spinning at the same speed. Again, just throwing out a guess here, I'm not knowledgeable about this stuff at all.

 

Good guess, as this is more or less what it means. A type of mechanical clutch activates at a defined speed and provides a direct mechanical system between the car's engine and it's transmission input shaft.

 

Aman answered the question in regards to lock up.

Are you referring to torque converter stall speed? In the simplest terms, it's the point were the torque converter overcomes load and begins moving the turbine.