There is a rated difference of 1 mpg. With so many variables I doubt even a side by side comparison would be conclusive. My educated guess, theoretically, the 4x4 would suffer slightly but not enough overlook the option if the need is there. I've had it on my last 2 trucks & have yet to use it on either but it's reassuring to have it.
A forum community dedicated to Ram 1500 diesel owners and enthusiasts. Come join the discussion about performance, ecodiesel, towing capacity, reviews, modifications, classifieds, troubleshooting, maintenance, and more!