Hello. I have a 2014 f350 with the 6.7, it's on a diet, tuned with 5" exhaust. I recently had my dash light up like a Christmas tree. Showing service advance trac, exhaust filter overloaded and it pops up the wrench symbol. Tune is bullydog sotf through the sct bdx. Had the setup for a little over 6 months and haven't had any issues with it. But now I'm getting a u0401 code and when I put the truck in drive the transmission immediately goes into 5th gear and will not drop back down into 1st. I tried re-tuning a couple different times with the same setup and got no results. I left the batteries unhooked all night hoping it would clear itself up but no joy. Any input would be awesome. Thanks.