The bolt was on the same side as the 17mm filler bolt, but higher and toward the front of the tranny case. It's a 5mm inner hex bolt. I looked for a5s-390r tranny diagrams but found no info on this bolt. When I removed it, there was a slow and continuous drip of presumably tranny fluid. After I realized my mistake, I replaced this and filled through the correct filler port.

Test drove and so far so good. Anyone know what that smaller bolt goes to?

Thanks.