2003 CHEVROLET EXPRESS 2500 Structurebody Problems

I WAS TRAVELING ON THE HIGHWAY AT THE SPEED OF 50 MPH AND THE VAN SUDDENLY BEGAN TO VIOLENTLY SHAKE AND SHUDDER FROM THE FRONT WHEELS AND UP AND INCLUDING THE SHAKE OF THE STEERING WHEEL. I SLOWED THE VEHICLE DOWN BY BRAKING TO 35 MPH AND IT SLOWLY STOPPED SHAKING. THIS HAS BECOME A REGULAR ISSUE WITH THE VEHICLE AND I HAVE TAKEN IT FROM SHOP TO SHOP AND MECHANICS CANNOT FIGURE OUT THE PROBLEM. I FEAR FOR MY FAMILY'S SAFETY AS WELL AS MY OWN WHEN DRIVING ALONE IN THIS VEHICLE. IT HAS BEEN A YEAR SINCE THIS HAS BEGUN. MECHANIC HAS CHANGED THE SHOCKS FOR THE VAN AND IT HAS BEGAN TO VIOLENTLY SHAKE AND SHUDDER MORE FREQUENTLY. I NEED TO KNOW WHY THIS IS HAPPENING. I OWN A CHEVROLET EXPRESS 2500 (2003). *TR

I HAVE A 2003 CHEVROLET EXPRESS VAN 2500 THAT THE PAINT JUST STARTED FALLING OFF IN LARGE FLAKES ON THE REAR AND SIDE DOORS, AND THE FRONT HOOD. I HAVE TRIED TOUCH UP PAINT TO TRY AND STOP THE PEELING, BUT IT HAS NOT HELPED.WHEN I WASH THE VEHICLE OR IT RAINS MAKES THE PROBLEM WORSEN BY FILLING UP POCKETS BEHIND THE PAINT. THIS IS A MY COMPANY VAN WHICH HAS DECAL LETTERING ON IT. THE FLAKING IS STARTING TO GET TO THE LETTERING. IF IT CONTINUES, I WILL LOOSE APPROX. $800.00 TO A $1000.00 IN DECAL LETTERING PLUS THE VAN LOOKS TERRIBLE FOR A COMPANY VAN. THE COLOR OF THE VAN IS WHITE. I HAVE NOTICED MANY GM CARS AROUND WHERE I LIVE THAT HAVE THIS PROBLEM. I NEVER REALLY NOTICED UNTIL MY VAN STARTED TO DO IT. MANY OF OUR CITY POLICE CARS WHERE I LIVE ARE WHITE...