Exhaust Manifold Pipe Replacement

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. If equipped with a 6.0L or 8.1L engine, remove the exhaust muffler.





8. If equipped with a 6.0L or 8.1L engine, perform the following:
1. Remove the clip around the engine harness and the oxygen sensor pigtail.
2. Disconnect the connector position assurance (CPA) retainer.
3. Disconnect the oxygen sensor electrical connector.
4. Remove the oxygen sensor.





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





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





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





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





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





20. If equipped with a 6.6L engine, remove the exhaust manifold pipe.
21. 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.





13. If equipped with a 6.6L engine, slide the exhaust pipe clamp down and around the pipe connection.

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


Notice: Refer to Fastener Notice in Service Precautions.

14. Tighten the exhaust pipe clamp and muffler nuts.
^ Tighten the clamp to 40 Nm (30 ft. lbs.).
^ Tighten the nuts to 40 Nm (30 ft. lbs.).





15. If equipped with a 6.0L or 8.1L engine, install the exhaust manifold pipe nuts.
Tighten the nuts to 50 Nm (39 ft. lbs.).
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:
1. Apply anti-seize compound GM P/N 12377953 or equivalent to the threads of the old oxygen sensor.
2. Install the old oxygen sensor.
Tighten the sensor to 42 Nm (31 ft. lbs.).

18. If equipped with a 6.0L or 8.1L engine, and the exhaust manifold pipe was not replaced perform the following:
0. Connect the oxygen sensor electrical connector.
1. Connect the CPA retainer.
2. Install the clip around the engine harness and the oxygen sensor pigtail.





19. If equipped with a 6.0L or 8.1L engine, remove the exhaust muffler.
20. Install the transmission support crossmember.
21. Install the transmission support crossmember bolts.
Tighten the bolts to 95 Nm (70 ft. lbs.).





22. Lower the transmission onto the transmission support.
23. Install the transmission mount to transmission support nuts.
Tighten the bolts to 40 Nm (30 ft. lbs.).
24. Remove the support from the transmission.
25. Lower the vehicle.