LUCA LADY LUCK LUCA LC LLL Eaton Detroit Truetrac Differential 28 Spline 1.20in Axle Shaft Diameter 2.73 5.13 Ratio. The Detroit Truetrac is a helical gear style, limited slip differential that maximizes wheel traction and enhances driving characteristics. Maintenance free, it features smooth, automatic operation in forward and reverse. Its versatility makes Detroit Truetrac the ideal traction solution for almost any type of vehicle. Optimized Torque Bias Ratios Deliver Max Acceleration And Handling No Special Lubrication Or Friction Modifiers Needed Helical Gear Limited Slip Differential Durable; Smooth; Quiet Operation Works In Forward And Reverse Ideal For Most Vehicles Automatic Engagement