-snip-
and then the replacement trans doesn't
like to shift on start up, only after a short warmup, so it looks like I
have to eventually repeat the effort after rebuilding the trans.
-snip-

You're probably right. After my auto tranny died, I went thru the archives
and compiled info from several posts regarding various symptoms and
syndromes regarding the autos. The symptom you describe seems to have been a
consistent sign of an impending failure and rebuild. In my case, it came
sooner than later. Good luck with it.

Cya,
Robert