I have been looking for a 2000-2002 Ram 3500 for years (not apples to apples I know but), I have almost pulled the trigger several times but the issue becomes the cost people want. I know their is a ton a value in an older diesel, no emissions, cool factor, etc but at a point it makes no sense. It is still a 15 y/o truck that will have issues that need to be addressed and cant tow near (Legally) what the new ones can.
It’s a very tough market for older vehicles, you have to find someone that can see the value and has cash because KBB and NADA don’t.
I think you should keep it and I’m not trying to be a jerk. I think you have an awesome truck! These are just the issues I have run across trying to get my own awesome truck.