The Gerodisc hydro-mechanical type limited slip differentials has been successfully developed for production. The same basic principles can be modified and adapted for racing use, with significant features, such as an adjustable engagement threshold and bias torque levels. Similar to the production versions, the racing differential can be designed as speed sensitive only or as both a speed and torque sensitive limited slip differential. Additionally, the racing versions may allow switching between these two modes. In this paper, the operation principle and general construction of the Gerodisc racing differentials and coupling devices are discussed as well as a brief description of adjustment features. Some laboratory test data is also included.