Thank you - as soon as I read your post I knew! It's axle fluid. I had changed bearings, races, seals and axle fluid in 2021, so the idea it was leaking didn't come to mind. I don't drive the truck as much since I've retired. Also, the 75w90 synthetic axle lube is still mostly clear, looking more like brake fluid until you actually rub it between your fingers. Now I just need to discover why both sides starting leaking at the same time? Thanks again. I appreciate your response.