Just back from a ride and oil under the bike near the swingarm, (2010 FXDWG) Where the swingarm bolts onto the tranny there are 2 what look like breather holes.

Checked the transmission fluid and it's full still at the top mark. Wasn't a lot of oil, about a teaspoon. It looks like it's coming from around the 2 holes cos they're pretty wet with oil. No cracks or anything, just oil around the 2 holes.

I first noticed it when I stopped for lunch, it was only a drop or 2, then after the next fuel up was about a teaspoon, now just got home and it's only a few drops.

Does anyone know what those 2 holes are? they're about 5mm maybe 6 and on the transmission where the swingarm bolts on to.

Thank heaps.

OK those 2 holes are only casting holes,,,lucky there. It's solid alloy.
So maybe the speed sensor??

Put a new o-ring on the speed sensor...Now I can see where the oil is coming from....
OIl seeping out the back of the starter motor, there's a little drain hole right at the end of it.
Why would there be oil seeping out the starter?

could be coming from the primary

Not sure if this refers to your issue,  Mate I ride with had oil leaking from his crankcase it was a dyna, oil would just weep out of this paticular area, found that the crankcase castings were porous (little air bubbles when casting)  which happens with castings sometime. Harley replaced the engine cases under warranty.

Apparently Evinrude Outboard Engines make the casting for HD bikes