Partial update. Aplogies for all the detail, but figured it may be useful.

I removed the throttle position linkage at the trans lever and then pulled the throttle lever full forward (towards front of car) and wired it in place. Checked fluid level again hot in N. Took the car for a spin and this is what I observed.

1) From a standstill the 1-2 upshift occurred at 3500+ rpm when in D. With the linkage disconnected I would of guessed the shift would occur very early.

2) Again as I mentioned in my first post if I dropped from D to 2 at lower RPM (trans still running in 1st), when I thought it should have already 1-2 upshifted I could get it to 1-2 upshift immediately.

3) As I was running out of time/daylight/fuel/road I did a couple accelerations from a stop in D and after it 1-2 upshifted at 3500+ rpm I dropped the gear selector into 2. When I did this at first I thought it was downshifting making me wonder if it was in 3rd already (possibly in 2nd from stop?), but I don't think this was the case as the tach barely moved (car is probably cruising at about 35 mph at this point). The hood is off the car and I could see the engine flex (like when it shifts, but more subtle) when this happened. So now I am wondering if this was not a 3-2 downshift, but rather something else being released (as the tach barely moved), but the trans felt like it was being freed up or something?

Sorry for the poor description, but it doesn't help when you are new to this. In reading my thought was maybe somehow it has something (band) applied that should not be at that time and dropping from D to 2nd on the selector helped remove this?

In any event as I said I ran out of time, but figured this may provide insight? Not ignoring other posts, but figured disconnecting the throttle position lever was the first thing to do and figured the other info may be useful.

So in review even with the throttle position lever disconnected 1-2 upshift was occurring at over 3500 rpm and there is something happening after the 1-2 upshift as if I drop the gear selector into 2 it feels as if something is happening (feels like a milder gearshift, but doesn't show up on the tach).

At this point I figured I need to check in for advice as I don't know how to proceed and don't want to toast the tranny.

Thanks for all the help. Really appreciate it.