Hi. First of all, the AW transmissions are funny -- if you just pull the dipstick and look at it, you won't get the correct level indication (it's something about how the fluid collects around the area) -- it will always read way overfilled.
You have to (with the engine running, of course) pull the dipstick once (and wipe it, of course, with a lint free rag), and then reinsert it all the way (past the clip the presses against the handle) and then pull it again -- then you get an accurate reading.

Anyway, what I'm going to write may seem counterintuitive to you (given your dipstick reading of being overfilled), but read on ...

Actually, if you check the dipstick when the engine is off (although I know that you properly have to check it when the engine is running), the fluid level will in fact be a few inches(!) over the scale, seeming as if you're about 5 or 6 quarts ovefilled (although there is only 7.4 qts of fluid in the transmission, but that's what it will seem). My point, however, is that the transmission fluid may really be SO low that it's not even pumping fluid around in it (as if the engine wasn't running), thus giving you the erroneous "several quarts overfilled" reading on the stick that you normally get when you check it with the engine off. You see the logic?

Also, the return line to the transmission (by which you do a transmission flush with the hose, etc.) is the upper line. However, I don't know why it wasn't squirting out of the line when you detached it -- but it's consistent with my gut feeling that the fluid isn't being pumped because it's really very low!

I'm thinking, by your writing that the transmission was overfilled by about two quarts, makes me think it's not being pumped at all by the engine's running and its really extremely LOW on fluid -- and remember that cold temperature reduces the fluid's volume! Your fluid level might have been only marginal until now!

If it was me, I'd add a quart or two and see if the transmission starts pumping. It can't hurt -- it's dead right now, isn't it?