I just got it a couple days ago and i took it offroading in the snow but there was no mud. When i go over 40 mph its starts to shake and when i go faster it shakes more. Idk if its because the snow is making the wheels off balanced or what.
My friend's dad's truck does that, but he never goes off roading with it, he just drives really fast, and accelerates very fast. That is what the rams do, they are not really built that well in the suspension area. But they do have great looks and power.
check suspension, wheel alignment and balance
check the engine block for some type of vacuum leak, like in the heads or headers, which could be causing it to shake at higher RPMs