Ok so two machined surfaces. If there is no gasket between the two castings then are there any internal seals used to seal the shafts that go between the two cases? If there are, that's what I would suspect is leaking.
While focusing on this problem Need guidance on why my fuel gauge got scorched for a while, I went back to the leak. The top of the two castings is dry, the sides are dry until the lower bolts. I tightened one side some last night with a 1/2" breaker bar. It may have been 1/8-1/4 turn max. The other side had hydraulic lines in the way and the casting had a funky bump that prevented a 1/2'' drive socket from fitting. I used two combination wrenches, but the wrenches started flex before the bolt turned. I'll buy a 3/8'' drive breaker bar and try again. That is the only place that is wet.