The control of the oil strain within the lock-up clutch is done by means of two valves: the relay valve plus the signal valve. In this type of arrangement the signal valve controls the strain on one facet from the relay valve, which controls the pressure in the lock-up clutch. https://torque-converter-clutch97306.boyblogguide.com/33254124/the-2-minute-rule-for-torque-converter-clutch