96 extended cab 2.4L tacoma leaking

2 days ago, I found a thick black goo, most likely oil, on my garage floor under the back corner of the driver side cab. Today I found a similar spot on the passenger side. Any idea how oil could get in those places? Blue Shop paper towel wouldn't pick it up. Could it be brake fluid? I checked all fluids and were to full mark. I ran engine for 5 minutes then backed it out and back in. Breaks an transmission felt normal.

 

Outside the frame? On both sides?

Taco was driven through some road debris? Like newly oiled down road?
Weird.

 

Splashed through the same puddle of whatever that goo is on the road near your house or on a route you take frequently?

 

Thank you the good suggestion ControlCar, but truck has been parked for about 4 months. It wasn't driven thru any tarred/chipped road that I can remember.

 

ControlCar & axnJackson, would the goo only be in those 2 small spots? Wouldn't it be on quarter panels and in tire wells?