My converter will not lockup or it was locking and isn now. Whats wrong?
The converter clutch operation from the transmissions perspective is quite simple. The lockup solenoid is energized and, in the case of the 95 and up 4L60E, the PWM solenoid is turned on. This strokes a valve in the pump and the lockup clutch is engaged. The clutch assembly inside the converter consists of two seals and a clutch. The solenoids engage and the fluid is directed to the converter clutch piston via the TCC valve in pump, which applies the clutch. From a converter perspective, there are only two reasons this might not happen. One would be the seals are damaged or bad. This is unlikely if the clutch has been applying and has suddenly stopped or now applies intermittently. The other possibility is the lining has come off the converter clutch. However, if this has occurred you will hear a grinding/rubbing sound from the converter and there will be metal in the pan. From a transmission perspective there are several possibilities. The O ring on the input shaft could have gone bad
