Changing to Redline 70W140 this afternoon but can not find a gasket on Summit or Fel Pro or anywhere. Does everyone go back with RTV? I got on thier site and saw a new product- usually used Black RTV before but this looks promising, anyone used this yet? "PermatexÂ® Gear Oil RTV Sealant OEM specified. Specially formulated to withstand the harsh gear oil environment found in differentials and transfer cases. Because gear oil has friction modifiers that break down normal RTV and cause leaking, this specialty silicone has been tested to OEM specifications to ensure complete sealing. As a gasket maker it seeks and seals leak paths that cut gaskets cannot."