The center section I bought from Mancini Racing has on the break-in steps paper what oil to use but specifically says "Do Not Use Valvoline Gear Oil" any one know why? I have Valvoline gear oil already. The diff is a Auburn Pro series. Nowhere on the Auburn web page does it say not to use that oil. I have emailed Mancini but haven't received a response. Just wondering if any one else knew anything.