Like Mark we have a 2008 Freightliner Chassis/Cummins. engine with particulate filter. No problem with it. You will see the temp rise slightly and then fall back within a minute or two. I am not sure this is the 'cleaning' process or not. One time we had an icon come on the screen showing something like a puff of smoke - that may have been the cleaning.
Sometimes we will travel quite a bit on long trips, then again (health issues) the coach may sit for a few months. I understand the DEF will get stale after it has been opened and added. I don't know about the system as to how it works, but I do move an occasional diesel truck with DEF in my P/T job. Never had any problems.
