I bought my 2015Dodge Durango Rt v8 in December, I bought the v8 thinking I could save gas by using The Eco mode that is on the vehicle .well I turned the Eco button on and the car sounds like your hitting a rumble strip . It's loud , shifts funny , and vibrates the steering wheel . We brought it in to be checked and they said there is nothing wrong , that's the way Chrysler made the vehicle . The car is trying to kick down to a four cylinder from an eight cylinder so they told me it has to compensate somewhere . I personally think that Chrysler threw the Eco in the car knowing that it doesn't work , to be able to sell the v8 to people worried about the gas Mileage. but. If the Eco doesn't work and I bought the car thinking it did they should give me some money back or fix the problem . In stead they would only offer a few free oil changes . For the money I'm losing in gas I think that's hardly enough .