2004 Dodge Ram 2500 front end shaking

I bought a 2004 dodge 2500 4x4 4 door automatic.I was wondering if you could help. The problem is when im driving around 60 or above and hit a bump in the road the front end shakes outta control till I pull over to reduce my speed to about 40 mph then it stops. Any of you guys experience this or have any suggestions. Please let me know