Exhaust Pipe: Service and Repair

Exhaust Manifold Pipe Replacement (6.0L, 6.6L, and 8.1L Engines)

Removal Procedure






1. Raise and suitably support the vehicle.
2. Support the transmission with a suitable transmission jack.
3. Remove the transmission mount to transmission support nuts.
4. Raise the transmission off of the transmission support.






5. Remove the transmission support crossmember bolts.
6. Remove the transmission support crossmember.






7. Depending on which side is being replaced, perform one of the following steps:
- Remove the exhaust muffler nuts.
OR
- Loosen the exhaust pipe clamp.
8. Remove the necessary exhaust system hangers so that the pipes can be separated.
9. Use a jack stand to support the exhaust.






10. If equipped with a 6.0L or 8.1L engine, perform the following:
10.1 Remove the clip around the engine harness and the oxygen sensor pigtail.
10.2 Disconnect the connector position assurance (CPA) retainer.
10.3 Disconnect the oxygen sensor electrical connector.
10.4 Remove the oxygen sensor.






11. If equipped with a 6.0L or 8.1L engine, remove the exhaust manifold pipe nuts.
12. Using the transmission jack, lower the transmission slightly.






13. If equipped with the 6.6L engine, remove the exhaust muffler nuts.






14. If equipped with a 6.6L engine, loosen the exhaust pipe clamp.
15. Slide the exhaust pipe clamp up onto the exhaust pipe adapter.






16. If equipped with a 6.0L or 8.1L engine, remove the exhaust manifold pipe.
17. Slide the exhaust manifold pipe hanger out of the exhaust pipe hanger bracket.
18. Discard the exhaust manifold pipe seal.






19. If equipped with a 6.0L engine, with RPO Y91, remove the exhaust manifold pipe.
20. Slide the exhaust manifold pipe hanger out of the exhaust pipe hanger bracket.
21. Discard the exhaust manifold pipe seal.






22. If equipped with a 6.6L engine, remove the exhaust manifold pipe.
23. Slide the exhaust manifold pipe hanger out of the exhaust pipe hanger bracket.

Installation Procedure






1. If equipped with a 6.6L engine, install the exhaust manifold pipe.
2. Apply water based lubricant to the exhaust pipe hanger bracket, in order to aid in installation.
3. Slide the exhaust manifold pipe hanger into the exhaust pipe hanger bracket.






4. If equipped with a 6.0L engine, with RPO Y91, install a new exhaust manifold pipe seal to the exhaust manifold pipe.
5. Install the exhaust manifold pipe.
6. Apply lubricant to the exhaust pipe hanger bracket, in order to aid in installation.
7. Slide the exhaust manifold pipe hanger into the exhaust pipe hanger bracket.






8. If equipped with a 6.0L or 8.1L engine, install a new exhaust manifold pipe seal to the exhaust manifold pipe.
9. Install the exhaust manifold pipe.
10. Apply lubricant to the exhaust pipe hanger bracket, in order to aid in installation.
11. Slide the exhaust manifold pipe hanger into the exhaust pipe hanger bracket.






12. If equipped with the 6.6L engine, install the exhaust muffler nuts until snug.

Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.







Important: Ensure that the manifold pipe is square to the exhaust pipe adapter.

13. If equipped with a 6.6L engine, slide the exhaust pipe clamp down and around the pipe connection.
14. Tighten the exhaust pipe clamp and muffler nuts.
- Tighten the clamp to 15 Nm (11 lb ft).
- Tighten the nuts to 40 Nm (30 lb ft).






15. If equipped with a 6.0L or 8.1L engine, install the exhaust manifold pipe nuts. Tighten the nuts to 50 Nm (39 lb ft).
16. Using the transmission jack, raise the transmission.






17. If equipped with a 6.0L or 8.1L engine, and the exhaust manifold pipe was replaced perform the following:
17.1 Apply anti-seize compound GM P/N 12377953 or equivalent to the threads of the old oxygen sensor.
17.2 Install the old oxygen sensor. Tighten the sensor to 42 Nm (31 lb ft).
18. If equipped with a 6.0L or 8.1L engine, and the exhaust manifold pipe was not replaced perform the following:
18.1 Connect the oxygen sensor electrical connector.
18.2 Connect the CPA retainer.
18.3 Install the clip around the engine harness and the oxygen sensor pigtail.
19. Install the exhaust pipe/catalytic converter to the vehicle.
20. Install the exhaust system hangers.






21. Depending on which side is being replaced, perform one of the following steps:
- Install the exhaust muffler nuts. Tighten the nuts to 40 Nm (30 lb ft).
OR
- Install a NEW exhaust pipe clamp. Tighten the clamp to 44 Nm (33 lb ft).






22. Install the transmission support crossmember.
23. Install the transmission support crossmember bolts. Tighten the bolts to 95 Nm (70 lb ft).






24. Lower the transmission onto the transmission support.
25. Install the transmission mount to transmission support nuts. Tighten the bolts to 40 Nm (30 lb ft).
26. Remove the support from the transmission.
27. Lower the vehicle.