If you cannot find the source after wiping clean the current leak residue then you might consider a UV Fluorescent leak detection dye. You can find this dye on Amazon for sure and maybe at a local DIY retailer. You also need a UV light or a blue light flashlight (about $12). Helps to be in darker circumstances when using the light. It is blatantly obvious when you see it. Can be for pan leaks or cracks, whatever. It doesn't hurt your fluid at all and lasts a long time.
There could be several sources for a leak. I would look at pan gasket then seals. Let the Forum know what you find. It helps others.
