Shift Finger Rail Error

I am having some problems with my 2006 Mack Pinnacle with an Eaton Fuller transmission. Truck will start off the day fine meaning run smoothly for the first 2-2:30 hours sometimes as much as 3. Then the transmission shifting display will flash F and stay in the gear that it was in and not upshift or down shift until the truck is pulled over and given about 5-10 minutes to shut down and reset. This occurs most commonly in 9th or 10th gear but happens occasionally in the 4-5 range when at the landfill. The first occurrence will generally not be followed up for another hour to hour and a half, but then it starts occurring extremely frequently as in every 5-10 minutes. Computer was connected when the code was active today and read an error in the shift finger rail. This code is not inactive in the morning and solely pops after the truck has been used as explained above. I have already replaced the XY shifter and am at a loss for how to proceed. Any suggestions?