Hey everyone. I am new here but have always worked on cars and truck. I am looking at getting a 2018 Ram 3500 Limited with the Cummins turbo diesel. I have looked everywhere and cannot find anything in aftermarket axles gear ratios and I was wondering if anyone know if the 3.42 ratio is the highest I can get. If it is, are there any ways to get the engine to spin slower at cruising speeds. I am also looking at different tunes for fuel economy and power. Not at the same time. Just when I need them. Thanks for your advice in advance. If anyone knows anything about these trucks that is good or bad, please let me know. Thanks.