I do not have a Navistar but I did purchase a new RAM Eco Diesel truck a year ago. I love the truck but am very disappointed with the amount of times I have had it into the dealership for reprogramming. It goes into regen probably once a week. Thanks to the new government pollution controls on diesel engines. I don't believe the manufacturers have a very good solution.
I'm glad our 2001 diesel motorhome has an older engine. I don't think I could take two vehicles with the same issues.
Good Luck let us know if you find a solution or they give you a new engine.
