Why does your 1991 Pontiac sunbird torque converter unlock at 37 mph?

The torque converter in your 1991 Pontiac Sunbird unlocks at around 37 mph to enhance fuel efficiency and improve engine performance during cruising conditions. This unlock feature allows the engine to operate at a more efficient RPM, reducing slippage and enabling a direct connection between the engine and transmission. By disengaging the torque converter, the vehicle can better utilize power and optimize fuel consumption, particularly at higher speeds.