Begin by raising and supporting the vehicle and removing the spare tire to replace the Muffler on 6.0l, 6.6l, and 8.1l engines while installing adjustable jack stands under the rear axle. To replace the Muffler on vehicles with an 8.6 or 9.5 inch ring gear you must disconnect the rear axle vent hose with its swivel clip from the rear brake crossover pipe. When working on a ring gear that measures 10.5 inches keep the same procedures in mind. Begin by taking off the lower nuts and bolts from the rear
Shock Absorbers before possibly dropping the rear axle. 6.0l and 8.1l vehicles require you to remove their exhaust Muffler nuts and loosen the
Exhaust Pipe clamp. Helpful assistance will be needed to support the exhaust Muffler while you must loosen the catalytic converter coupling nuts for 6.6l engines. For 6.0l or 8.1l engines remove insulators from frame hangers and move the Muffler backwards to separate from the catalytic converter and recover the insulators from the Muffler hangers. To remove the exhaust manifold pipe gasket carefully pry up the catalytic converter coupling clip using a small flat-blade screwdriver to release the locator button. Slide the Muffler rearward until full disengagement is reached before removing the insulators from the frame hangers for 6.6l engines and the exhaust Muffler gasket if needed. A new band clamp requires installation when the Muffler operates as a standalone component. Mark the existing clamp position, remove its weld with grinding until completely separated then install the new clamp. When installing the Muffler on 6.0l or 8.1l engines, reposition the original
Oxygen Sensor with gm p/n 12377953 anti-seize compound and tighten its mounting bolts until they reach 42 nm (31 ft. Lbs.). To install the Muffler on 6.6l engines position the Muffler locator button directly across from the catalytic converter coupling groove and push the Muffler in place until it fits properly into the coupling clip. Cut four strips of dielectric grease to coat the Muffler hangers and frame hangers. Next apply a new exhaust Muffler gasket and an exhaust manifold pipe gasket before installing them into position. Assisted by another person, push the Muffler so it meets the catalytic converter. Torque the catalytic converter coupling nuts to 45 nm (33 ft-lbs) after you set their initial torque tightness values. Position the new band clamp on the intermediate Exhaust Pipe using alignment reference points on 6.0l or 8.1l engines while actively avoiding positioning the bolt underneath the pipe. Following this, install exhaust Muffler nuts before tightening the Exhaust Pipe clamp bolt to 44 nm (33 ft. Lbs.). Use an axle lift to raise the rear axle then install lower bolts and nuts on shock absorbers until they reach 95 nm (70 ft. Lbs. Torque). Reinstall the vent hose of the rear axle and link the swivel clip to the brake crossover pipe if required. After doing this you can remove adjustable jack stands. Carefully install the spare tire before lowering your vehicle.