Well I'll take a stab at it. Gaskets are used where the front pumpkin bolts into the housing and where the rear cover bolts on also. I would think they should be available from many of the truck part dealers, Jim Carter, Chevy Duty ect.... As far as what to paint the rear housing with, from the factory they would have been finished in a satin black color (semi gloss). Preference is up to the painter on brand and type of paint. Myself when I get to that part I will probably use Rust-O-Leum Satin Black. Gaskets and seals should also be available for the axle shafts and the ball on the back of the transmission. Check your breather on the axle housing to make sure it is not stopped up with dirt. Hope this helps.