Detroit Truetrac differentials are a helical gear style limited slip differential. From a high-level system view, the units are constructed similarly to an open differential
– except all gears are helical and the “pinion” gear is split into two intermeshed gears. Because of the three gear tooth mesh interfaces, the design must have lash. While all Truetracs (and helical gear differentials in general) have internal lash, units with preload are less noticeable. Typically, Truetracs have a maximum lash of three to four degrees side-to-side between gears. This is normal and required for the superior torque transfer design of the product.