The electric wiring in a 700R4 transmission works by controlling the lock-up mechanism of the torque converter clutch. This setup typically requires a 12-volt electrical circuit.
A 700R4 transmission is commonly installed in vehicles that lack a computerized system. The wiring kit for the transmission generally includes a vacuum switch, pressure switch, wiring harness, gasket, mounting screw and splice connectors. The wiring is usually configured inside the transmission pan and the application of a voltage supply hydraulically engages or disengages the transmission gears. When the vehicle is in overdrive, which typically occurs in fourth gear, the torque converter clutch is automatically enabled under normal engine operation. Otherwise, when the car is either accelerating or switching to a lower gear, the clutch is disabled. This lockup style wiring design prevents overheating of the transmission.