Torque CONVERTOR Lock-Up

The torque convertor lock-up clutch is engaged as a function of throttle position, output speed, oil temperature, gearshift and shift program. Lockup is possible in 2nd, 3rd, 4th and 5th gears but is usually restricted to 4th and 5th gears. During a gear shift the TCM controls the amount of slip of the lock-up clutch to enhance shift quality.