904 tranny leak

I would try looking a little higher . There is few things there that may make it see as though the pan is leaking.... the pan is the lowest point so it will always flow to the pan gasket area.
Check the leaver seal area there are 2 seals there, (1) the main leaver seal and (2) the throttle shaft seal. Also look at the neutral switch area there is a seal on that as well. Also the filler tube oring may cause it too.Take a can of brake clean spray it down blow it off and run the car for a while you should see it seeping from where ever its coming from.
If it turns out to actully be the pan gasket again, make sure the pan bolt holes are not lumped up from over tightening if they are, then tap them down flat and install a new pan gasket...... NO IMPACT GUN ! GL to ya