Front Suspension problems of the 2014 Ford F-350

3 times, while driving at highway speeds (55 -70 mph) the truck front end has entered into a violent oscillation, with steering wheel juddering. Rapidly slowing to a stop or <25 mph has allowed control of vehicle to be regained. Fortunately this has only happened in light traffic and while following a straight road allowing vehicle to be pulled to shoulder. I am not sure what would happen if vehicle was in a turn or in heavy traffic unable to reach the emergency lane. First time this happened I assumed front shocks were bad and had them replace. However this has not fixed the problem as it has happened twice since, after running over expansion joints on a bridge/interstate interface and expansion joint on the road. Have since learned this is not an isolated issue unique to my vehicle.