WE WERE TRAVELING IN THE SOUTH PASS OF BIG HORN NATIONAL PARK. THE GRADES WERE LONG AND STEEP. A PERSON PASSED US AND PULLED OVER AND STOPED US AND SAID WE WERE ON FIRE. THE COACH FILLED WITH SMOKE ND I GOT OUT AND FOUND THAT THE AREA ABOVE THE EXAUST PIPE HAD MELTED DOWN ON TO THE PIPE CATCHING ON FIRE AND BURNING UP EVERYTHING IN THE COMPARTMENT CAUSEING $3000.00 OF DAMAGE. ON MY OLDER MOTERHOME IT HAD HEAT SHEILDS ABOVE THE EXAUST TO PREVENT THIS. ALL THE OTHER BRANDS I HAVE LOOKED AT HAVE ALSO MADE PROVISIONS TO PREVENT THIS FROM HAPPENING. I HAVE ALSO LOOKED AT OTHER MOTORHOMS LIKE MINE AND SOME OF THEM ARE AT HIGER RISK THAN MINE. I HAVE TALKED TO TIFFIN BUT THEY SEEM TO BE "OH WELL" ABOUT THE ISSUE. I THINK ALL OF THIS MODEL AHOULD BE CHECKED AND MEASURES TAKEN. THE PEOPLE THAT HELPED ME OUT ON THAT MOUNTAIN SAID I WAS NOT THE ONLY ONE THAT HAS HAD THIS PROBLEM BUT I DON'T KNOW WHAT KIND OF MOTORHOMES THEY WERE.