Bob. I used Permatex Ultra Black hi-temp rtv silicone gasket maker, the number on the tube is 598B. Make sure you go around each hole with the sealant (on the cover) and put some sealant on the threads of the bottom (the middle bolt, I think it is the drain bolt if you don't want to remove the cover. Silicone (sealant) dries in one hour and fully cures in 24 hours. Used it on my fass coolers. Let it set overnight and fill trans with fluid and no leaks. Hope this helps. Bought the weather tech floor mats that was in one of your post. Thanks for the tip.