What port should the AT vacuum line be tapped from? It shifts from 1st almost instantly to 3rd (and bogs down of course) and does not kickdown even though the kickdown solenoid appears to be working electrically. Modulator has been replaced and governor seems to work. I hate to drop the trans pan if I don't have to.

Should be from teh one on the passenger side of the intake runner.  Full intake Vacuum.

 

Shifting from 1st to 3rd immediately suggests that the governor second stage may be stuck open

Swapped governors and modulator and still the same thing. I am planning to drop the pan and see if there is something stuck in the pickup tube if vacuum doesn't work.  What's the best spray cleaner to use on transmission components?

According to the manual and my experience with this transmission you need to adjust the band. It is fairly easy to do and is supposed to be done every 60k as part of the regular maintenance schedule.