First make sure to wear protective goggles and gloves and exercise caution when it comes to exercise service. To replace the Muffler. The Muffler is serviced as an assembly with an
Exhaust Pipe and Tail Pipe and if Tail Pipe is after-market it is raised up using the frame to drop the raid axle. Begin by raising the vehicle. Screw out the nuts that fasten the Catalytic Converter pipe to the Muffler flange for a 4.3l engine that has a single Catalytic Converter pipe. For a 4.8l/5.3l/6.0l engine with two Catalytic Converter pipes, loosen the clamp of the right Catalytic Converter and remove the nuts that hold the left Catalytic Converter to the Muffler flange. Remove the Muffler assembly hanger pins from the exhaust hanger insulators based on the wheelbase and exhaust system length of the car, this can be a two person job because of the weight of the exhaust system. Lift the Muffler assembly over the rear axle and pull it towards the front on the vehicle. For installation, place the Muffler assembly from the front of the vehicle by lifting it over the rear axle, which may need two people. Mount the Muffler assembly hanger pins to the exhaust hanger insulators. If fitted with a 4.3l engine, then fit the retaining nuts and new gasket to the front of Muffler and tighten the Catalytic Converter to Muffler retaining nuts to 48 nm (35 ft. Lbs.). For a 4.8l/4.3l/6.0l engine, fit a right Catalytic Converter in the Muffler, and tighten the clamp nut to 54nm(40 ft. Lbs.). Replace a new gasket and right nuts retaining left the Catalytic Converter to the Muffler flange, ensure the exhaust system align properly, then the tighten-right Catalytic Converter clamp to 54 nm (40 ft lbs.) & the Catalytic Converter to the Muffler flange nuts to 48 nm (35 ft lbs.). Finally, lower the vehicle.