1990 SUNCREST 2500 Suspensionfront Problems

AT 20MPH ON FREEWAY EXIT WITH ROUGH SURFACE FRONT WHEELS STARTED VIOLENTLY SHAKING SIDE TO SIDE UNTIL ALMOST TOTALLY STOPPED. ON CHECKING IT IS DETERMINED THAT THERE IS EXCESSIVE PLAY IN THE STEERING BOX. THE STEERING WHEEL EXHIBITS THIS ALSO AS IT MOVES ABOUT 2 TO 3 INCHES BEFORE VEHICLE STARTS TO TURN. WE ALSO NOTE THAT LEFT FRONT WHEEL RUBS DRAGGING ON FULL RIGHT TURN. THE UNIT WAS JUST FRONT END ALIGNED, AND THE TIRES ROTATED. THIS IS AN OSHKOSH CHASSIS, NOW OWNED BY FREIGHTLINER. THE MOTORHOME MANUFACTURER, R & R CUSTOM COACH WORKS WENT OUT OF BUSINESS AT THE END OF THE 1993 MODEL. THERE IS NOT A FREIGHLINER DEALER IN SAN JOSE, CA. THIS SEEMS TO BE THE ONLY PROBLEM IN THE FRONTEND. THIS IS A 35 FOOT CLASS A MOTORHOME. I HAVE ONLY DRIVEN IT ABOUT 700 MILES AND NO PROBLEMS UNTIL THIS HAPPENED. *AK