Thanks for your response... and sorry I did not make it clear that:
(a) I have already purchased a standard OE parts transmission service kit...
(b) and thus I'm planning to replace the filter etc., but...
(c) I'm looking for ideas/opinions from others as to what might be the best
(1) changing the filter,
(2) draining, inspecting and cleaning the pan
(3) flushing the torque converter using my "FLUSH" adapter
AND I trust you can appreciate, there are numerous options as to the sequence
for doing these... and I had hoped others who have much more knowledge of and
experience with the "O1M" might throw in their ideas!
Years ago, when I first faced a similar task with a 1967 FWD Olds Toronado,
to get the fluid out of the torque converter I ended up simply, disconnecting
the cooler line and let the transmission's pump purge any fluid that remained
after dumping the pan and changing the filter.
If I can remember, I then put in the new filter and a full charge of cheap fluid
which I ran for a couple days... and then changed the filter again and put in
the best fluid I could identify as appropriate!
I think the Olds Toronado tranny's TorqueConverter alone held
6 quarts of fluid... 10 or 11 total!...
but that was when fluids were a lot cheaper relatively speaking !