2016 Freightliner Cascadia automatic eaton trans. smartshift.Cummins

Hello community,

I recently had a problem with my 2016 freightliner cascadia (smart shift automatic, eaton tran. cummins engine). I received a blinking Check Trans light on my dash board; the truck would rumble and I had to come to a complete stop. The truck stayed in 7th gear and would not shift to neutral. I placed the shifter to neutral and applied the breaks and turned off the truck. I turned it back on after 30 seconds and the 7th gear was still showing on my dial display. I then disconnected the power and let the truck sit on the side of the highway for 20 minutes. I restarted the truck and everything worked as if nothing happened. I could not reproduce the problem until a few days later while on a load (first time-just got done with a load). I replaced the PNDB (causing other issues), I replaced the XY shifter and harness, and a few other piddly stuff. The truck seemed to work until the next day it started acting up again with the same issue. I wasnt able to pull the codes from ranger during the incident but i managed to pull other codes before changing the XY shifter. OBVIOUSLY it was not the XY shifter or harness. What other issues could it be? I need some help with a game plan to diagnose this sucker. View attachment 504474

 

If its not the FC19 low voltage, what else could it be?