Method and system for releasing hydraulic pressure of automatic transmission

A system for releasing hydraulic pressure of an automatic transmission, comprising:

• a detecting module detecting vehicle speed, throttle opening, turbine speed, and oil temperature in a transmission;
• a transmission control unit generating a control duty based on the detected values transmitted from the detecting module, and calculating a delay time according to the oil temperature;
• a solenoid valve generating a control pressure according to the control duty of the transmission control unit;
• a pressure control valve controlled by the control pressure of the solenoid valve and a feedback pressure opposing thereto, and supplying an operating pressure;
• a pressure switch valve controlled by the control pressure of the solenoid valve and a reducing pressure opposing thereto, and supplying a part of the operating pressure transmitted from the pressure control valve back to the pressure control valve as the feedback pressure;
• and
• a switch valve supplying the operating pressure transmitted from the pressure control valve to an off-going element.