Catalytic converters for 2005 workhorse with GMC 8.1 vortec

Many mufflers have had their lives extended by wrapping them with sheet metal. The problem is that since you seem to have a rust problem in your area, the inside muffler baffles can also rust and break loose. When this happens it can increase the back pressure in the muffler which can cause poor performance/fuel mileage and may eventually cause engine damage.