Thanks for the symptom with what it was doing. I looked that up and is common on Jeep cause lots of people with a no downshift trans issue. You also need to check the TPS throttle position sensor for proper voltages with a voltmeter as this controls the tranny shifting. The TPS voltages are into the ECU not the TCU trans controller. Also found a few links you should read.
https://www.wranglerforum.com/f282/transmission-wont-downshift-help-817970.html
http://midsouthjeeps.com/forum/topic/260-automatic-transmission-wont-downshift/ this is about a plugged vent hole (plugged with mud)
https://www.jeepforum.com/forum/f310/won-t-downshift-stop-1201294/
governor pressure solenoid and sensor, under filter tray that you just did

So this is 3-4 more things to check. Lots of other people have had this problem too. good luck.