Supersedes Technical Service Bulletin Group 42 number 12 ? 13 dated September 5, 2012. Oil leak in the area of the Quattro sports rear differential (PR-PDU, PDR, or GH2) side flange, or axle shaft inboard flange. Insufficient sealant on the protective cap on the inboard constant velocity joint at the rear differential on vehicle with a sports differential. Optimized use of sealer in production from 07/10/2011.