The rear differential (commonly known as the Haldex) fitted to many European four-wheel drive cars (4Motion to be precise) from Volkswagen and Audi (Tiguan, Sportwagen, Golf Alltrack, Golf R, A3, and Q3) is made up of clutch plates and metal discs that wear down over time due to friction, causing deposits in the oil and the differential filter. This clutch is activated by hydraulic pressure created by a motor attached to it.

They are quite delicate when it comes to service. The manufacturer’s recommendation is to change the oil every 45,000 km, or 3 years. In our experience, the filter is already very dirty at this mileage, which can damage the pump if it runs out of oil. In order to prevent costly repairs, we recommend preventive service every 35,000 km, or 3 years.

See below for a comparison of before and after service: