The torque converter is a fluid coupling that transfers power produced by the engine to the transmission above 500 to 800 RPM. These couplers allow your car to idle without driver input, and most will give tell-tale signs of impending failure before it occurs
Overheating is perhaps the most common TC problem, and usually occurs when there is a transmission fluid pressure drop, as might occur when the fluid is too low or the filter is clogged.
This is another common TC problem, and causes your car to resist acceleration while the engine continues to rev. The most common cause is low or overheated transmission fluid.