The most common failure point on the Audi Sport Differential is the pair of spider gears at the heart of the differential. These gears take 100% of the torque delivered to the rear end. On higher powered and/or heavier cars, it’s common to see them break during launches and 1-2 shifts, usually destroying the casing and ring/pinion gears in the process. Photos below. The 4-pinion upgrade replaces the stock differential with a stronger unit utilizing 4 spider gears instead of 2.
4-pinion upgrade service includes:
Split-housing 4-pinion differential casing with new taper roller bearings
2 additional OEM spider gears
2 new outer axle oil seals
4 new inner axle oil seals
New pump motor assembly gasket
New pinion shaft oil seal
2 new pinion shaft bearings