if you don't see the leak on the floor overnight, that means it's just seeping out of the seal or gasket. it's hard to say if it's OK or not because you don't know how long it's been leaking. i'm not aware that there's a warning light or even a sensor for ATF fluid level.
the only way to figure out the ATF level is to warm up the ATF (between 85 and hundred something), then open the fill screw, if the liquid seep out, you got enough. if not you need to add.