The control of the oil pressure from the lock-up clutch is done by two valves: the relay valve and also the sign valve. In this sort of arrangement the signal valve controls the strain on just one facet with the relay valve, which controls the strain from the lock-up clutch. https://danteckquw.getblogs.net/66828766/helping-the-others-realize-the-advantages-of-torque-converter-clutch