For the rest of you, the only way to get the fluid out is to remove the transmission pan. Odds are, you don't change it enough anyway. The sludge was built up beyond the capacity of the filter or the magnet to contain it. On the A-727, the filter is held in place with three Phillips screws, perhaps the best design we've ever seen for a transmission filter. We don't entirely trust the press-on type.
Access is limited.
Put the pan back on but don't refill the transmission. If your truck is equipped with single exhaust like ours was, you'll have to remove the Y-pipe. If you are less ambitious, the Y-pipe can be unbolted from the manifolds, with sufficient application of PB Blaster. With the exhaust out of the way, unplug the battery and remove the starter. Remove the oil filter.