I had trouble finding a gasket for the same application. You could cut your own gasket by tracing the cover on gasket material. Or you could use Permatex "Right Stuff" without a gasket. I used this on my 2 spd differential cover and is real easy to use. It comes in a pressure can and also in a cartridge that goes in your common caulking gun. I noticed recently that they sell it in shorter tubes for the caulking gun, as a full size cartridge goes a long way and is a little pricey. This stuff is very easy to use and quick, and you don't have to let it set up before driving the truck. On the applications I have used it on you don't get that creep of oil or grease after awhile.
Also, my oil plug was rounded off, so I just took a file to it, making it a bit smaller and I just use a crescent wrench to remove and replace.
