Trac-Loc, short for Traction-Lock, is a type of limited-slip differential used in vehicles to improve traction. It allows power to be distributed to both wheels on an axle, helping to prevent wheel spin during acceleration, especially on slippery surfaces. This enhances vehicle stability and control, making it beneficial for off-road driving and performance applications. Trac-Loc systems often use clutches or gears to manage the torque distribution between the wheels.