Exhaust Manifold Pipe Replacement 6.0L, and 8.1L Engines

1. Raise and suitably support the vehicle. Refer to Lifting and Jacking 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. Remove the clip around the engine harness and the oxygen sensor pigtail.
11. Disconnect the connector position assurance (CPA) retainer.
12. Disconnect the oxygen sensor electrical connector.
13. Remove the oxygen sensor.



14. Remove the exhaust manifold pipe nuts.
15. Using the transmission jack, lower the transmission slightly.



16. 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 regular production option (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.

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



5. Install a new exhaust manifold pipe seal to the exhaust manifold pipe.
6. Install the exhaust manifold pipe.
7. Apply lubricant to the exhaust pipe hanger bracket, in order to aid in installation.
8. Slide the exhaust manifold pipe hanger into the exhaust pipe hanger bracket.

Notice: Refer to Fastener Notice in the Preface section.




9. Install the exhaust manifold pipe nuts.

Tighten
Tighten the nuts to 50 N·m (39 lb ft).

10. Using the transmission jack, raise the transmission.



11. If the exhaust manifold pipe was replaced perform the following:

11.1.

Apply anti-seize compound GM P/N 12377953 or equivalent to the threads of the old oxygen sensor.

11.2.

Install the old oxygen sensor.

Tighten
Tighten the sensor to 42 N·m (31 lb ft).

12. If the exhaust manifold pipe was not replaced perform the following:

12.1.

Connect the oxygen sensor electrical connector.

12.2.

Connect the CPA retainer.

12.3.

Install the clip around the engine harness and the oxygen sensor pigtail.

13. Install the exhaust pipe/catalytic converter to the vehicle.
14. Install the exhaust system hangers.



15. Depending on which side is being replaced, perform one of the following steps:

•	Install the exhaust muffler nuts.

Tighten
Tighten the nuts to 40 N·m (30 lb ft).

•

or

•	Install a NEW exhaust pipe clamp.

Tighten
Tighten the clamp to 44 N·m (33 lb ft).




16. Install the transmission support crossmember.
17. Install the transmission support crossmember bolts.

Tighten
Tighten the bolts to 95 N·m (70 lb ft).




18. Lower the transmission onto the transmission support.
19. Install the transmission mount to transmission support nuts.

Tighten
Tighten the bolts to 40 N·m (30 lb ft).

20. Remove the support from the transmission.
21. Lower the vehicle.