At least it felt and smelled like diff fluid. Getting the car out of the garage for cars and coffee this morning I go back inside to get the Miata ready for my wife to drive and I see an oil drip a little less than a tablespoon in the area where the rear of the 8 had sat overnight.

This evening I got underneath and found similar fluid on the passenger side of the fuel tank. But there's not enough of anything coming from the pinion area for it to have slung and run down. In fact that little bit of residue pictured seems to be more excess grease from the u-joint rather than gear oil.

Very odd. I'll have to keep an eye on it.

 

other than that it looks pretty spotless under there, must not have much mileage?

 

Yes, just over 7,500. It's done a good bit of sitting for the past 10 years. I was planning to change transmission and diff at 10K miles but I might just go ahead.