Muffler: Service and Repair
Muffler ReplacementRemoval Procedure
Caution: Refer to Hot Exhaust System Caution in Service Precautions.
Caution: Refer to Exhaust Parts Removal Caution in Service Precautions.
1. Raise and suitably support the vehicle. Refer to Vehicle Lifting.
2. Remove the oil pan skid plate bolts and plate, if necessary.
3. Remove the spare tire, if necessary.
4. If servicing a Suburban/Yukon XL with Regular Production Option (RPO) Z55, disconnect the chassis harness from the following electrical connectors:
^ Electronic suspension rear position sensor (1)
^ Rear shock (2)
5. Install adjustable jack stands under the rear axle, if necessary.
6. If equipped with a 8.6 or 9.5 inch ring gear, remove the rear axle vent hose from the rear axle, if necessary.
7. Remove the vent hose swivel clip from the rear brake crossover pipe, if necessary.
8. If equipped with a 10.5 inch ring gear, remove the rear axle vent hose from the rear axle, if necessary.
9. Remove the vent hose swivel clip from the rear brake crossover pipe, if necessary.
10. If equipped with a 11.5 inch ring gear, remove the rear axle vent hose from the rear axle, if necessary.
11. Remove the vent hose swivel clip from the rear brake crossover pipe, if necessary.
12. Remove the rear shock absorbers lower bolts and nuts, if necessary.
13. Lower the rear axle using the adjustable jack stands, if necessary.
14. If equipped with a 6.0L or 8.1L engine, perform the following:
^ Unclip the oxygen sensor connector from the frame.
^ Disconnect the Connector Position Assurance (CPA) retainer.
^ Disconnect the oxygen sensor electrical connector.
15. If equipped with a 6.0L or 8.1L engine, perform the following:
^ Unclip the oxygen sensor connector from the support.
^ Disconnect the CPA retainer.
^ Disconnect the oxygen sensor electrical connector.
16. If equipped with a 6.0L or 8.1L engine, perform the following:
^ Unclip the oxygen sensor connector from the support.
^ Disconnect the CPA retainer.
^ Disconnect the oxygen sensor electrical connector.
17. If equipped with a 6.0L engine, perform the following:
^ Unclip the oxygen sensor connector from the frame.
^ Disconnect the CPA retainer.
^ Disconnect the oxygen sensor electrical connector.
18. If equipped with a 6.0L or 8.1L engine, remove the exhaust muffler nuts.
19. Loosen the exhaust pipe clamp.
20. With the aid of an assistant, support the exhaust muffler.
21. If equipped with a 6.6L engine, remove the exhaust muffler nuts.
22. With the aid of an assistant, support the exhaust muffler.
23. If equipped with a 6.0L or 8.1L engine, remove the insulators from the frame hangers.
24. With the aid of an assistant, slide the muffler rearward in order to remove the muffler from the catalytic converter.
25. Remove the insulators from the muffler hangers.
26. Remove the exhaust manifold pipe gasket, if necessary.
27. If equipped with a 6.0L engine, with RPO Y91, remove the insulator from the frame hanger.
28. If equipped with a 6.0L engine, with RPO Y91, remove the insulators from the frame hangers.
29. With the aid of an assistant, slide the muffler rearward in order to remove the muffler from the catalytic converter.
30. Remove the insulators from the muffler hangers.
31. Remove the exhaust manifold pipe gasket, if necessary.
32. If equipped with a 6.6L engine, remove the insulators from the frame hangers.
33. With the aid of an assistant, slide the muffler rearward in order to remove the muffler from the exhaust muffler pipe.
34. Remove the exhaust muffler gasket, if necessary.
35. Remove the insulators from the muffler hangers.
36. If equipped with a 6.0L or 8.1L engine, remove the oxygen sensor if the muffler is being replaced.
Installation Procedure
Notice: Refer to Exhaust System Clearance Notice in Service Precautions.
1. If equipped with a 6.0L or 8.1L engine, and the muffler was replaced re-install the old oxygen sensor.
2. Apply anti-seize compound GM P/N 12377953 or equivalent to the threads of the old oxygen sensor.
Notice: Refer to Fastener Notice in Service Precautions.
3. Install the oxygen sensor.
^ Tighten the oxygen sensor to 42 Nm (31 ft. lbs.).
Important: Apply lubricant to the insulators to aid in installation.
4. If equipped with a 6.6L engine, install the insulators to the muffler hangers.
5. Install a new exhaust muffler gasket.
6. With the aid of an assistant, slide the muffler forward in order to install the muffler to the exhaust muffler pipe.
7. Install the insulators to the frame hangers.
Important: Apply lubricant to the insulators to aid in installation.
8. If equipped with a 6.0L engine, with RPO Y91, install the insulators to the muffler hangers.
9. Install a new exhaust muffler gasket.
10. With the aid of an assistant, slide the muffler forward in order to install the muffler to the exhaust muffler pipe.
11. Install the insulators to the frame hangers.
12. If equipped with a 6.0L engine, with RPO Y91, install the insulator to the frame hanger.
Important: Apply lubricant to the insulators to aid in installation.
13. If equipped with a 6.0L or 8.1L engine, install the insulators to the muffler hangers.
14. Install a new exhaust manifold pipe gasket.
15. With the aid of an assistant, slide the muffler forward in order to install the muffler to the catalytic converter.
16. Install the insulators to the frame hangers.
17. If equipped with a 6.6L engine, install the exhaust muffler nuts.
^ Tighten the exhaust muffler nuts to 40 Nm (30 ft. lbs.).
18. If equipped with a 6.0L or 8.1L engine, install the exhaust muffler nuts.
19. Tighten the exhaust pipe clamp bolt.
^ Tighten the exhaust muffler nuts to 40 Nm (30 ft. lbs.).
^ Tighten the exhaust pipe clamp to 40 Nm (30 ft. lbs.).
20. If equipped with a 6.0L engine, perform the following:
^ Connect the oxygen sensor electrical connector.
^ Connect the CPA retainer.
^ Clip the oxygen sensor connector to the frame.
21. If equipped with a 6.0L or 8.1L engine, perform the following:
^ Connect the oxygen sensor electrical connector.
^ Connect the CPA retainer.
^ Clip the oxygen sensor connector to the support.
22. If equipped with a 6.0L or 8.1L engine, perform the following:
^ Connect the oxygen sensor electrical connector.
^ Connect the CPA retainer.
^ Clip the oxygen sensor connector to the support.
23. If equipped with a 6.0L or 8.1L engine, perform the following:
^ Connect the oxygen sensor electrical connector.
^ Connect the CPA retainer.
^ Clip the oxygen sensor connector to the frame.
24. Raise the rear axle using the adjustable jack stands, if necessary.
25. Install the rear shock absorbers lower bolts and nuts, if necessary.
^ Tighten the rear shock absorbers lower bolts to 95 Nm (70 ft. lbs.).
26. If equipped with a 11.5 inch ring gear, install the rear axle vent hose to the rear axle, if necessary.
27. Connect the vent hose swivel clip to the rear brake crossover pipe, if necessary.
28. If equipped with a 10.5 inch ring gear, install the rear axle vent hose to the rear axle, if necessary.
29. Connect the vent hose swivel clip to the rear brake crossover pipe, if necessary.
30. If equipped with a 8.6 or 9.5 inch ring gear, install the rear axle vent hose to the rear axle, if necessary.
31. Connect the vent hose swivel clip to the rear brake crossover pipe, if necessary.
32. If servicing a Suburban/Yukon XL with RPO Z55, Connect the chassis harness to the following electrical connectors:
^ Electronic suspension rear position sensor (1)
^ Rear shock (2)
33. Remove the adjustable jack stands from under the rear axle, if necessary.
34. Install the spare tire, if necessary.
35. Install the oil pan skid plate and bolts, if necessary.
^ Tighten the oil pan skid plate bolts to 20 Nm (15 ft. lbs.).
36. Lower the vehicle.