and people still want to argue that the 6.7L's are great trucks....
problems like this are completely unheard of on the 5.9L's of any generation.
anyway...A tip for you fatboy since you are stuck with a 6.7L
stop babying the truck. the easier you drive it, the more problems you are going to have.
if you want to prevent soot buildup you need to run it hard. drive it like you stole it and get that exhaust HOT. get an EGT gauge and load up and pull a long grade and try to hold 1200* on the pyro for as long as you can. that will literally start burning off all of the soot buildup in your exhaust.