1994 Dodge Ram Shaky Truck

Yeah I was just wondering my truck will start shaking violently while driving it. It seems to be when I go over a rough patch in the road and going over 60 miles and hour or so. The cab feels like it is about to come off the frame and then I slow down and the problem seems to correct itself. My friend had the same problem and he fixed his steering stabilizer bar and that seemed to fix his problem. But no such bar exists on Dodge's before 1998. I have no idea what it could be any suggestions would be great.