Hello!

Okay, so I'm sitting at a long red light. I start to think (it was really long). Why/How does a car w/ an automatic transmission not stall when the car is not moving? You know the transmission is still "engaged" since you can move the car by only slightly letting off the brakes.

Please keep in mind that I know almost nothing about what make the car go, besides gas and my heavy foot. I only know enough to be dangerous.

Just wondering, thanks!

 

The torque converter serves as a liquid coupling between the engine and transmission. This is the part which allows the engine to run when the vehicle is stopped. The torque converter serves other purposes as well.

Visualize two electric fans, set facing each other. Turn one on. The breeze generated by the powered fan causes the unpowered fan blades to turn. This is a fluid coupling in which the "fluid" is air. In your car's torque converter the fluid is automatic transmission fluid, and the two "fans" are positioned very close to each other for better efficiency.