Thought my pinion seal puked

Took the 'Cuda out of storage to fill up the gas tank for the first time. Later that day it snowed a couple inches and then after the it melted away a week or 2 later this is what I saw under the rear end. First thought was that the pinion seal had croaked, but after inspection of the stain it appears to be fuel. Any initial thoughts on what might be leaking? After driving a bit and lowering the level it doesn't seem to be leaking now.