Thought my pinion seal puked

It's been too cold to get out and under it just yet. I have only had it a couple months. But there was on old sending unit in a box in the trunk area when I bought it. Like I said, doesn't seem to be leaking now that the level is down some. Hoping it's that gasket.
If it is a new fuel sender that is leaking, it should be the new, thinner lock ring that would cause it. The gasket is fine. Hopefully the old lock ring is in the trunk with the old sender.