For that heavy of a work load I hate to say it but that trans is going to tear up. Believe it or not dodge had to limit the power of the cummins engine specific to what the 68rfe can handle. I do a lot of them and typical failure is OD clutch just gives up. It is a very thin set of single sided clutches and they get hot one time (like u did) then they warp start to drag and just burn up on normal driving. It is a terrible design they all do it and no one has a fix yet. Trans go makes a decent shift kit that does help but don't do that until warranty is up. I can get you a part number I do it to every one I build here at work. Honestly I am sure you like your dodge but for that kind of work the only truck that can handle it and not fail is a chevy or gmc duramax Allison combo. The Allison is heads and shoulders above all other one ton transmissions and only one we don't see failures on that often. We do over 100 trans a week here where I work huge place in fl and we maybe see 5 Allison 1000 a year vrs say 200 48re 50 68rfe 200-300 e4od 4r100 5r110 and even now seeing a lot of ford 6 speed failures which they said was compareable to an Allison and they burn up just as bad as early 5 speed fords. Chevy was smart and went to a trans that was built for trucks hauling way more then any 3500 truck will see. Dodge did offer a 12k option of the Asian seiki that is a good trans but hard to find and really only see in the bed delete trucks that turn into tow trucks mostly. I would keep complaining until they change the whole trans. Work it hard and break it before that warrany is up so they have to do it or u will be stuck out of pocket. If u keep up that line of work get a gm vehicle and never worry again. Lt1z350@bellsouth.net if need to reach me direct to ask other questions.
Joe