I'm not sure about the 4wd gasket but when I re-sealed my oil pan on my Frontier I was told the same thing. I ended up using some oil-safe sealant from Autozone. It's been a year and a half and it's still holding up.
Here is a link-
http://www.autozone.com/selectedZip,85711/initialAction,accessoryProductDetail/initialR,NONAPP9952/shopping/selectZip.htm