I am guessing that it isn't the pan gasket at all. I went though this on two of my cars. The trans leaks and travels to the lip of the pan and then follows the low point and it sure looks like the gasket is leaking. I replaced pretty much all seals and it still leaked. It turned out it was a crack in the dipstick tube right where the O ring fits. This was way back 20 years ago. I have since stopped 3 trans leaks on other first gens with the same exact problem.