This shaking sounds like the very same symptoms I encountered in an older Dodge Caravan 3.3L V6 on a 5000 mile road trip. Yours may be a very similar drivetrain. Two mechanics told me it was definitely not the axle (failing CV joint). A third solved the problem with a new axle.
Usually, a failed CV joint makes a diagnostic clicking, but none of my failed axles on that van (there have been several) ever clicked, though the shaking was pretty severe that one time. I don’t know how to diagnose this, but that’s what happened to me. I have heard that with these vehicles, there’s something to do with alignment of the engine with respect to axle position, meaning that if the motor mounts are not holding the engine in precisely the right spot, it tears up CV joints. Evidently, there are some measurements to be made and the mounts loosened so the engine can be moved to precisely the right position. I know no further details, have not bothered yet to investigate, so this may be bogus, but it’s what I was told at a reputable parts store which has sold me several axles. I suspect that mine has an issue with that, but since it’s nearing retirement, I may not bother to solve that.