Operation: Functions like a full manual valve body; whatever gear you select that is the gear the trans will be in. Gear changes made with factory column shifter or floor mounted shifter. Shifter must have 7 positions PRND321 Transmission will not shift up or down without moving the shifter. Maintains OEM forward shift pattern and engine braking on downshifts. Operates with continuous full line pressure for firmer shifts, less clutch slippage and cooler operating temperatures. Automatic torque converter lock up. Converter locks up when transmission is shifted into 4th gear (overdrive) and unlocks when downshifted. Wo1rry f1ree operation; no accidental stalling at stop lights. Light indicates converter "locked". Converter can also be manually controlled with the 3 position switch which is included. Fitment： For 1994-up Transmission (1991-1993 must have round case connector) Compatible with GM Vehicles equipped with 4L80E Transmissions Package Includes: 1x 4L80e Stand Alone Trans Controller