So what is worse "on a FUSO" , the frame flexing as it was designed with loads under gvw or concentrated forces on the frame from a mounting system proving loading and flexing other than the designers intent. . The reason I ask is my box is mounted directly to the frame. There are about 155000 miles on the rig and it has been around. The frame was inspected and looked fine. Am I living on borrowed time? Or is frame isolation just a concept of complexity? Would love everyone's thoughts.