Helical Limited Slip Differential For Chrylser & GM 11.5 Inch 30 Spline 11.5AAM Chy & GM 30 Spline Helical Type Positraction (Like Tt) Yukon Gear & AxleYukon gear type helical LSDs use floating helical cut worm gears that lock the torque down when wheel slippage occurs, transferring torque to the tire with the best traction in a smooth progressive manner. Yukon gear type helical limited slip differentials know how to put the power down. They use floating helical cut worm gears that lock the torque down when acceleration or wheel slippage occurs, transferring torque to the tire with the best traction