The RS3 Haldex controlled rear diff is a fantastic torque-controlled unit that drives the rear wheels in the Audi RS3 / QRS3 / TTRS. The downsides for these when tuned include lack of traction (open differential); and also gear breakage due to very sharp edges on the gear teeth acting as stress risers, and not particularly strong materials used.
Until now, there hasn’t been many options for these and customers who break them have been left either playing roulette with a second hand wrecked unit, or paying through the nose for a new genuine unit that may do the same thing again. This is due to the fact that VAG consider these units closed / unserviceable internally, and so all of the internal repair components cannot be purchased. Not anymore!
