Somethin just don't seem right here! Like there is something mechanically holding the pan away? Warped pan? Bolts bottoming out or threads poorly cut? I would not expect to see that much leakage with NO gasket (except maybe on a Harley). I don't remember if the inner surface of the pan is flat, but if it is, a piece of thick glass or a polished stone countertop and some 400 grit paper will quickly tell you if it's warped AND will leave a good sealing surface.