Theory Of Operation

The 1-2/4-5 Solenoid is activated when the Transmission Control Module (TCM) commands the transmission shifts from gears 1->2 / 2->1 or 4->5 / 5->4. The solenoid is only activated during the actual shift of the transmission. When the solenoid is activated, hydraulic pressure is applied to the proper shift elements in the transmission to allow the desired shift. Once the shift is completed the solenoid is turned off.