ARP 02A/early 02J Diff Bolt KitSince the factory differential and ring gear are riveted together at the factory, when installing a Wavetrac differential or a new ring and pinion in your 020, 02A, 02J, 02Q or 02M transmission, you must drill out the rivets and replace them with special bolts and nuts. These are available from Volkswagen and also other aftermarket sources. After losing confidence with the quality and or having been dumbfounded by the outrageous prices for these parts