Yesterday I was driving to my dads and went over some traintracks. As soon as I hit them (going about 35/40) my whole truck started shimmying like crazy. I pulled over really quickly and thought one of my front wheels was about to come off. I looked under it, checked u-joints, tie-rod ends, steering damper, and saw nothing out of the ordinary. I just got back in it and started on my way without any trouble the rest of the drive. I have a hint that it is one of the wheel bearings but im not sure. Maybe you guys can help me.