The pressure control solenoid, as well as the connector problem, are know to cause harsh shifts. The connector problem also sets off several codes.

My new Scangauge II also shows No Codes.

But is it showing 3rd gear switch, 4th gear switch, and TCC duty cycle/switch? Instead of looking at error codes, go to where it shows realtime data from the pcm, then go take the car for a test drive. watch those values and you should see the gear gear switch close and the TCC duty cycle go up as the PCM starts telling the transaxle to apply the clutch.

(edited to include 3rd gear TCC...I've been spending so much time with a 700R4 that I forget that other transmissions can do TCC in 3rd too )

ScangaugeII is not yet capable of showing those live codes. Bummer!

Not all scanners can show live data.