swainmedic430

So My 02 gmc sierra Hd duramax started out with what i thought was a transmission issue 7 months ago when you put the truck into gear the PRND on R and D would just flash and not go into gear could turn off truck and start it again and it would fix it go into gear and be fine for up to 2 to 3 weeks then spontaniously go into safe mode PRND would start flashing again but the DIC would reset or loss power whith this action. My transmission guy swarres its not the transmission that its electrical Ive changed everthing from the nuetral safty switch the tcm, ecm, ingnition switch, and the ingition barrel. still having issues with the DIC lossing power and spontaniously going into safe mode any ideals