A 700R4 transmission is a four-speed automatic transmission that was used in many General Motors vehicles from 1982 to 1993. It is an electronically controlled transmission, meaning it relies on various sensors and solenoids to control how it shifts. The main components of the 700R4 are the torque converter, which serves as a bridge between engine and transmission; planetary gearset; vacuum modulator valve (VMM); throttle pressure cable (TPC); shift pattern selector switch; kickdown servo motor or cable assembly; front pump assembly and rear output shaft seal. The VMM senses changes in vehicle load conditions by detecting manifold vacuum levels, while the TPC measures throttle position and sends signals to the VMM telling it when to upshift or downshift. The shift pattern selector switch allows drivers to select either Drive or Manual mode for more precise shifting if desired. Finally, the kickdown servo motor/cable assembly enables full power shifts when needed by controlling timing of upshifts based on driver input from their foot pressing down on the accelerator pedal.