Hello. I will be purchasing my first 3500 diesel SRW crew cab to tow our upcoming 5th wheel. I'm looking at used 2015-2018 year ranges with under 50K miles. Having never owned a diesel I've recently learned about all of the deleting (????) and programming people have done to their diesels. My question is if I buy from a non-Dodge dealer, how can I tell if the truck has been deleted or reprogrammed. Having never owned a diesel engine I want one that is stock. I don't want to pay a lot of money for a truck and then a year later have to spend a lot more money to fix it because somebody messed up the engine by deleting/reprogramming. Thanks in advance.