The seal should be available at a parts store like Carquest or napa. I,m not shure about the retainer gasket although I have a GM part # at the shop. You can use RTV on it. I,m not familiar with a felt gasket. It,s probably not used anymore with modern seals. Tighten the pinion nut securly as it does not use a crush sleeve. Put in a cotter pin.
