But I need/want to replace the filter. Remember, Rich also abused this thing in his 96 Park Ave Ultra before giving it to me a couple years ago.

Never abuse my vehicles any more than you do lmao.

It'* not abuse, your mearly locating the weakest part in your drive train!

Certainly sounds like great news. Glad to hear it,

Mealticket

Mike, Glad to hear u got it home and that it actually shifted getting there.
Let car warm up to 145F before driving off when its real cold out.
I assume your fluid level is good and that ur not low when hot in park on dipstick.
I just want to mention that accumulation of varnish from heat and older fluid can attack and things start to stick like, accumulator 1/2 /2-3 bores & valve body and even the solenoids.
If u can wait and is still shifting, I always do this before a fluid and filter drop, get a can of Seafoam TransTune which is known to improve shifting and dissolve varnish.
Then if safe to do so, drive for some miles with it in, I noticed a significant improvement quickly with a full can in my 97PA 4t65E. Have u got a shift kit in there or Dans spacer treatment.
One thing is for sure once the pan is down u'll see if anything is on the magnet etc and gain the DEX6 syn fluid.
Link to TransTune: Trans Tune - Sea Foam Sales Company
It looks and feels like reg trans fluid only it really does a good job on removing varnish.

I wanted to note that on the accumulator bores, the pistons were not sliding all that well (slightly sticky) until after I used the emory cloth 1000 grit sandpaper.
I used a circular /around motion inside the bores, to make them truly smooth.

I don't think I'd be doing any shift kit on a failing transmission. That just sounds like you're asking it to blow up. I had a shift kit in my 4t65e and the problems with it got worse at a faster rate afterwards.