GM 15798961
Muffler

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.

To replace the exhaust Muffler to a vehicle with a 1500, v8 engine or lu3, follow the steps of lifting and supporting the vehicle before lowering the spare tire. Remove exhaust Muffler nuts only by removing the Catalytic Converter. For 4.8l engine, lubricate the 3 insulators, at the Muffler assembly where the hangers are fitted, to make the removal easy and with the help of a by remove the insulators, 1, 2 from the front and rear Muffler assembly hangers. Second, remove the in sulator from the intermediate Muffler assembly hanger and remove the Muffler assembly by tugging it rearward until it clears the front frame crossmember viai the flange. For a 5.3l or 6.0l engine, repeat the procedure of lubrication and removal part for insulators (1, 2) and respectively. Do not over extend the flex couple while doing a removal or installation to avoid internal damage. For installation, if it has a 4.8 l engine, lubricate the 3 insulators once more to make the installation process easy thereafter mount and install the Muffler assembly with the help of another person and install the insulators (1, 2) and to their appropriate hangers. Repeat the process of lubrication and installation for a 5.3l or 6.0l engine. After that, install the Catalytic Converter into the exhaust Muffler nuts and tighten up to 45 nm (33 lb ft), return the spare tire to its place, and lower the vehicle.

Installation of the new Muffler on 1500 series vehicles starts by supporting the vehicle and lowering the spare tire when replacing engines using 4.3l, 4.8l, 5.3l, and 6.0l as power units. Start by removing the exhaust Muffler nuts which secure the Catalytic Converter. A 4.8l engine requires lubrication on the 3 insulator points entering the Muffler assembly hangers before their removal. With help, personnel can detach the insulators (1, 2) from the front and rear hanger points. Take out the intermediate Muffler assembly by first removing its insulator followed by pulling the assembly backward until the front frame crossmember flange clears. The procedure for insulators (1, 2) lubrication and removal must be repeated exactly as described for vehicles using 5.3l or 6.0l engines. Both flex couple installation and removal require careful handling to avoid damage to internal structures. To install the Muffler assembly with a 4.8l engine system you must perform a new lubrication of the 3 insulators before properly positioning the assembly then assisted installation of the insulators (1, 2) on the front and rear Muffler hangers followed by the insulator installation to the intermediate hanger. The installation procedure should be redone for vehicles equipped with 5.3l or 6.0l engines. Next proceed with installing the Catalytic Converter by attaching exhaust Muffler nuts while torquing to 45 n.m (33 lb ft). Once complete replace the spare tire and lift the vehicle down.

To replace the exhaust Muffler on a vehicle with a cab chassis and 6.0l engine, first, raise and support the vehicle properly. Remove the spare tire if necessary and jack stands under the rear axle if necessary, but it is highly important at this point to rely on talk. In case the vehicle has an 8.6 or 9.5 inch ring gear, get rid of the rear axle vent hose as well as the vent hose swivel clip from the rear brake crossover pipe. Just do the same thing for the rear axle vent hose and clip if the vehicle has a 10.5 inch ring gear. Then, unbolt and remove the rear Shock Absorber if it needs to be done, then lower the rear axle using the adjustable jack stands. Remove the exhaust Muffler to exhaust manifold pipe nuts and partially loosen the exhaust Muffler clamp" remove the heated Oxygen Sensor (HO2S) and lubricate the 4 insulators where the hangers of the Muffler assembly should be inserted for easy removal. With a little help, remove the insulators (1-4) from the front, intermediate, and rear Muffler assembly hangers, as well as the Muffler assembly. For type installation one must lubricate the insulators again, mount the Muffler assembly and secure the insulators (1-4) onto the hangers. Replace the ho2s and be careful to follow fastener caution guidelines. Tighten the Muffler clamp (exhaust Muffler) to 47 nm (35 lb ft) and shake Muffler to Muffler personalize (exhaust manifold) pipe nuts to 45 nm (33 lb ft). On a different note, it will be wise to raise the rear axle using the adjustable jack stands if they are needed then install and tighten the nuts pressed on the rear Shock Absorber lower bolts to 95 nm (70 lb ft). If necessary, install the rear axle vent hose, connecting the vent hose swivel clip to the rear brake crossover pipe. Finally, be sure to remove the adjustable jack stands and use spare tire if necessary and lower the vehicle.

To change Muffler on 6.0l, 6.6l and 8.1l engines, first lift and support the vehicle, including remove spare tire if necessary, and under the rear axle install adjustable jacks if necessary. In the case of an 8.6 or 9.5 inch ring gear, plug the rear axle vent hose and swivel clip from rear brake crossover pipe, and when it comes to the vehicle with a ring gear of 10.5 inch follow the same steps. If necessary, remove the lower bolts and nuts of the rear shock absorbers, and then relieve the rear axle by lowering it using the adjustable jack stands. For 6.0l or 8.1l, remove nuts of the exhaust Muffler nuts and loosen the Exhaust Pipe clamp while carefully holding the Muffler exhaust to prevent it from falling down on the jobsite. For the 6.6l engine, also remove nuts from the exhaust Muffler and support the Muffler. Remove the insulators in the frame hangers for 6.0l or 8.1l engines, slide the Muffler rearward out of the Catalytic Converter, and then take off the insulators from Muffler hangers. If needed, peel off the exhaust manifold pipe gasket and for the 6.6l engine, take out the insulators from the frame hangers while sliding the Muffler towards the rear to separate it from the exhaust Muffler pipe. Pull off the exhaust Muffler gasket if necessary, and for 6.0l or 8.1l engines, pull out the Oxygen Sensor if the Muffler itself is being replaced. If the band clamp is not being replaced along with the Muffler, then the band clamp needs to be replaced, marking its position on the intermediate Exhaust Pipe, grinding and weld to remove the weld, and install a new band clamp. In case of installation that had the Muffler changed on 6.0l or an 8.1l engine, the old Oxygen Sensor needs to be re-installed with anti-seize compound gm p/n 12377953 on its threads, which were to be tightened to 42 nm (31 ft. Lbs. ). For the 6.6l engine, attach insulator to Muffler hangers and lubricate it to make it easier to install. Replace the exhaust Muffler gasket with a new one, then slide the Muffler forward to attach it to the exhaust Muffler pipe, before fitting insulators to frame hanger. For 6.0l or 8.1l engine, install the insulators to the Muffler hangers, lubricating them as well. Replace the exhaust manifold pipe gasket and slide the Muffler to the front connecting it to the Catalytic Converter and replace its riding to the frame hangers. For the 6.6l engine, the nuts for the exhaust Muffler must be tightened to 40 nm (30 ft. Lbs.). For 6.0l and 8.1l engines, set the new band clamp on the intermediate Exhaust Pipe next to the old one marked with a band clamp bolt, where tightening the exhaust Muffler nuts is meant to be done in such a way that the band clamp bolt installed in such a way that it would not be placed below the Exhaust Pipe itself. Secure the Exhaust Pipe clamp bolt to 44 nm (33 ft lbs). If required, raise the rear axle with adjustable jack stands, install the rear shock absorbers lower, bolts and nuts inserting them into place as tight as it gets 95 nm (70 ft. Lbs.). For 10.5 inch ring gear vehicles, install the rear axle vent hose and attach the vent hose swivel clip to the rear brake crossover pipe. For those with an 8.6 or 9.5 inch ring gear, fit the rear axle vent hose in and hook up vent hose swivel clip. Finally, take off the adjustable jack stands and install the spare tire if must and also lower down the vehicle.

Position the exhaust pipe with a NEW gasket to the turbocharger, ensuring the tab on the gasket faces inward, and loosely install the bolts.

Repeat the lubrication and installation process.

Remove the transmission mount to transmission support nuts, raise the transmission off the support, and take out the transmission support crossmember bolts and the crossmember itself.

Install the insulators to the muffler hangers with lubricant, install a new exhaust manifold pipe gasket, slide the muffler forward to connect it to the catalytic converter, and install the insulators to the frame hangers.

Install the rear axle vent hose and connect the vent hose swivel clip to the rear brake crossover pipe.

If necessary, raise the rear axle using the adjustable jack stands and install the rear shock absorber lower bolts and nuts, tightening them to 95 N.m (70 lb ft).

Remove the support from the transmission and reinstall the HO2S.