Kinda late for me as I got fed up and ripped out the POS autoshift. Think it was a simple corroded ground wire but it never was found after +10 K wasted at numerous FL dealers. Lost all faith Eaton factory techs. They were no help at all. Did not even seem to care about it.
Google [PDF]Troubleshooting Guide - Roadranger and it will pop right up. My guess is that the source of most of these auto shift problems is simple, small electrical contact failures. My trans would work just fine for several hours and then go nuts. After the truck sat and cooled off it would start and work perfectly until warm again which suggests a corroded ground somewhere OR any of dozens of low voltage tiny multi-pin connectors. Maybe if a diagnostic computer was hooked up right when the fault occurred(tech driving truck for 4 hours--no) it could have been found but it took hours before it acted up so the FL shops just changed parts based on the codes they had. In my case, every single electrical component in the trans was changed and never fixed the problem. They tried but the Eaton system is just too finicky and complex to easily find the problem. Converting to manual earlier would have saved thousands of wasted $. But, just bad luck in my case. By the way, shifting manually is very difficult to master but, while not perfect, I am floating the gears pretty good now. And, no longer worrying about the trans locking up and killing the truck and maybe me! That Eaton auto trans was a nightmare!