The Charge of the oil force inside the lock-up clutch is done by two valves: the relay valve as well as the sign valve. In this sort of arrangement the sign valve controls the force on one side with the relay valve, which controls the stress inside the lock-up clutch. https://martinubdcs.topbloghub.com/40590741/how-much-you-need-to-expect-you-ll-pay-for-a-good-torque-converter-clutch