As a matter of fact, I just got a call from the transmission shop yesterday afternoon. It was not particularly informative, since I pretty much already knew what they had to tell me. in a nutshell, there is something leaking inside the tranny, and it's going to have to be opened and inspected. Not really news, is it? I'm a bit disappointed, because just opening it up for diagnosing the problem is expensive. They have said that the actual fix is probably inexpensive (no more than a few hundred dollars, though on top of the diagnosis, that feels like a lot).
I just wanted to not have to worry about it, but I'm not sure that was the right decision. It would be much cheaper to warm up the car, not start in reverse, or try the Seafoam. But there is definitely a leak in the tranny somewhere, and I don't want to take chances.
I'll let you know what they find. I've asked for specifics as soon as they have them.