While at the dealer with my F350 Dually while doing the NOX update, I mention a rattling sound while backing and turning. Also, could feel rear end ratchet when making a sharp turn such as into a driveway.
DEALER found a FIX! There is an updated rear end from Ford for this condition that replaced the factory Dana rear end. In the 125 miles or so I had the truck back before the check engine light came back on after the NOX update, the replacement FORD rear diff was much quieter and smoother! Yeah!
I think the deciding qualifier was if it has the "camper" package with the underbed supports. Not sure what that has to do with anything, but it seemed better.
I am beginning to wonder if it was a major boo boo to have Ford go with Bosch for the fuel injection system.
They tried to get a design out the door as fast as possible, and in the process, used a lot of off the shelf parts that was not as mature as it should have been.
Getting rid of Navistar may turn out in retrospect to be much more expensive than keeping Navistar.