Most people know the benefits of upgrading a vehicle's suspension with polyurethane components, but the cab & body mounts are often overlooked. Factory mounts are constructed of rubber which break down over time due to exposure to various drive train fluids and the elements. As the body mounts break down, they become less and less effective at isolating the cab from chassis allowing road noise and vibration to transmit up through the body. In extreme conditions, worn body mounts can cause the body to shift on the frame and increase body roll as well as creating a number of other potential problems such as shift linkage and body panel alignment.