I have a 2022 6.7 with the 68RFE. Truck runs cross country towing 12k cargo trailer with 215,000 miles. In the past month, when I’m downshifting using the exhaust brake to slow down, it will jump to 4th gear and stay there. I’ll pull over, shut the truck off, restart and take off again and it’s back to normal. Sometimes this happens once a week, sometimes twice a day.


What’s going on here?

 

Pulled codes today and got P0868 and P0871

 

I just posted a similar thread . I am occasionally getting a PO846. On a few occasions , when I put it into "drive" , it goes right into 4th gear and is stuck there . I stop, shut off the engine , restart and its all fine except the check engine light and the PO846 code.

I will follow your thread for answers . .