I was out in Eastern Oregon last weekend checking out few remote places (away from all the crowds). I drove probably 100 miles on gravel roads where the road is even but with ribs like profile (small bumps), the vehicle handled terribly fishtailing many times where it felt like driving on ice/snow. Engaging 4x4 seemed to help but not whole lot. Any idea what is happening? I have taken Subaru and Prius on the same road few years ago and they did very well, but with Sprinter I felt I will lose control go to the ditch or worse fall off the cliff into the river at few hairy sections. The van is stock without any conversion, is this due to lack of weight or stock tires or tall vehicle means center of gravity is not optimal?