I suppose if there is a minuscule crack - it could possible need added stress from riding to open up. But I doubt it...
I was thinking about a little extra crankcase pressure. But that seems far fetched too. Would think if there was enough crankcase pressure to push oil through something it'd puke out the dipstick first. Or if the leak point was so large it needed so little pressure that the dipstick wasn't puked out that it leak more easily.
Ok, more data. Had forgotten about Matt's suggestion to spray deodorant on the area for more contrast. Against the red pan it was dark enough it was hard to judge much. Against the aluminum pan it appeared to be leaking from just above the pan and both running down and getting blown up just a bit.
With the extra contrast from the deodorant (Arrid X-tra Dry XXX) and after what may have been a perfectly timed short ride I'm now less sure of anything than I was before. And I'd become so unsure of anything here that that's saying something.
This leak (which never presented before the oil pan was removed and has then been consistent since that time) appears to be coming from the transmission side cover. Specifically directly beneath the forward most of the lower pair of bolts through the tranny side cover (i.e., the front bolt that goes through most exhaust brackets).
It's almost impossible to get an angle, position and lighting for a picture. This shows it though. Not well. But it does. Added a couple captions for orientation's sake.
Rode it just long enough to get the leak but not enough for it to spread forward or back any. Six miles got a nice straight and narrow vertical leak with the high point at the tranny side cover.
So....
I thought that high up it was gear oil not engine oil?
Why did it start there collateral to the pan being removed the first time (I'm still concerned about nascent case damage that only presented because of the other work -- this side cover bolt hole is directly adjacent to the pan bolt that is pulled when the pan is installed).
If those side cover bolt holes intrude in to the oil pan do they do so terminally through their end or just with the casting around the bolt hole facing the oil pan? If so still I'm still worried about a crack.
Am even less sure what I'm chasing now than when I thought I'd narrowed it down a bit before. This doth suck and annoy me.