Any torque converter consists of four major components among which the lock up converter plays a very important role. Although the lock up clutch is not part of the engine, it can make the car feel like the engine has a problem. It has many purposes and it is part of the transmission. At highway speeds this clutch can be applied and it will ensure a direct mechanical connection between the crankshaft and the input shaft, which will result in one hundred per cent efficiency between the engine and the transmission.
Even though the torque converter is engaged it never completely engages the way a manual transmission car clutch will. It will always slip a little which is a lack in its efficiency. Usually, to increase power and mainly fuel mileage, a lock up converter is added to an automatic transmission. This device is an electronic clutch that will engage the engine and will help the engine to completely engage without slipping. The lock up clutch is created to engage only in the top gear when the car is cruising, but not accelerating. It will disengage when the accelerator is pressed hard enough. A common problem for the lock up clutch is that in time it will wear out, especially if the car was operated in overdrive or top gear.
Usually, if the lock up clutch is bad one of three things will happen. The first thing is that the car will tend to rev up and down as it engages or disengages. In this case the car will not be able to keep the torque converter clutch locked up. The second thing that may occur is for the converter clutch to engage randomly in gears that it shouldn’t even engage in usually. And the third thing that may happen is to have a converter clutch which doesn’t want to disengage at all. As you slow down, the car won’t downshift and if you try to accelerate the car will have some difficulties in moving quickly. In some extreme cases the lockup converter will try to keep the vehicle moving when you try to slow down and stop or it will stall out and die.
Some people think that such problems come from the car’s engine because it causes the car to stall. And in some cases the check engine light will not show an error for the torque converter clutch. Most lockup converters are controlled by wires that plug into the transmission. So, it is possible on some models to simply disconnect this plug. But this is not a problem and it will only cause you to lose a little gas mileage.