DT12 Issue...

I have a 2016 Wetsern Star, DD15 with a DT12 in it...
Has been operating flawlessly, until a couple of weeks ago, I started getting overrevving between gears, not a constant issue but on upshifts it would ramp up between odd shifts, no issues on downshifts.

A couple of weeks ago I had to come to a hard stop (Nashville, rush hour!) once I once stopped the trans went into N and beeped at me, I couldn't get it to go into gear, air pressure was perfect, the only remedy I could think of was shutting off the battery for a couple seconds and when I started the truck back up, it shifted perfectly, no issues again for the next 1500miles, the over revving did continue.

Monday, when I was delivering my load, the trans shut down again and I repeated the process of powering off and it worked, this happened almost every time I came to a stop.

I am completely at a loss as to what it could be and would really appreciate any help with the issue.

 

I'm trying to get the codes, I shut it down overnight and still doing it, only happens when it downshifts coming to a complete stop and only takes me shutting off power for a second to get it to reset...

 

SPN 520999 FMI 7