If you don't pull a lot I would do the 2016 ecodiesel. The 2012 2500 with 90K is starting to get in to the maintenance period of it's life. Some go longer but your right on the edge of several things the Rams could have issues with. Injectors, ball joints, transmission issues depending how it was driven and maintained.

Also how do you intend to use it? Daily driver? Weekend truck? If daily I would stay away from a 2500 gasser (rams anyway) I had one and hated it. Under powered, gas guzzler, limited range. Mine was a 2013 Ram 2500 gas and I could barely get 300 miles out of a tank of gas and that was driving to squeeze every mile I could out of it (unloaded, no towing) Drove me crazy stopping for gas every couple days.

While everyone claims great mpg with diesels, the truth is (with the new ones) you are only going to see that with long highway miles. If you are commuting around town expect to be in the 13-15 mpg range if you baby it.

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