Catalytic Converter Replacement - Left Side 6.0L- Cab/Chassis

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. Loosen the exhaust muffler clamp (3).
8. Separate any necessary exhaust muffler insulators so that the pipe may be separated from the muffler.
9. Use a jack stand to support the muffler.



10. Remove the connector position assurance (CPA) retainer (3) from the left front heated oxygen sensor (HO2S).
11. Disconnect the engine wiring harness electrical connector (2) from the left front HO2S (1) electrical connector.



12. Remove the CPA retainer (8) from the left rear HO2S.
13. Disconnect the engine wiring harness electrical connector (4) from the left rear HO2S electrical connector (3).



14. Loosen the exhaust manifold pipe to exhaust manifold nuts.



15. Remove the left catalytic converter to exhaust manifold nuts.
16. Using the transmission jack, lower the transmission slightly.



17. Remove the left catalytic converter.



18. If the left catalytic converter is being replaced, remove the HO2S (1 and 4).

Important: A special anti-seize compound is used on the HO2S threads. The compound consists of liquid graphite and glass beads. The graphite tends to burn away, but the glass beads remain, making the sensor easier to remove. New, or service replacement sensors already have the compound applied to the threads. If the sensor is removed from an exhaust component and if for any reason the sensor is to be reinstalled, the threads must have the anti-seize compound applied before the reinstallation.

Notice: Refer to Fastener Notice in the Preface section.




1. If the left catalytic converter was replaced, perform the following steps:

1.1.	If reinstalling the old sensor, coat the threads with anti-seize compound GM P/N 12377953 or equivalent.

1.2.	Install the HO2S (1 and 4).

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




2. Install the left catalytic converter.



3. Using the transmission jack, raise the transmission slightly.
4. Install the left catalytic converter to exhaust manifold nuts.

Tighten
Tighten the nuts to 50 N·m (37 lb ft).




5. Tighten the exhaust manifold pipe to exhaust manifold nuts.

Tighten
Tighten the nuts to 50 N·m (37 lb ft).




6. Connect the engine wiring harness electrical connector (4) to the left rear HO2S electrical connector (3).
7. Install the CPA retainer (8) to the left rear HO2S.



8. Connect the engine wiring harness electrical connector (2) to the left front HO2S (1) electrical connector.
9. Install the CPA retainer (3) to the left front HO2S.



10. Tighten the exhaust muffler clamp (3).

Tighten
Tighten the clamp to 47 N·m (35 lb ft).

11. Install any necessary exhaust muffler insulators that were separated from the muffler.
12. Remove the jack stand from under the muffler.



13. Position the transmission support crossmember.
14. Install the transmission support crossmember bolts.

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




15. Using the transmission jack, lower the transmission onto the transmission support.
16. Install the transmission mount to transmission support nuts.

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

17. Remove the support from the transmission.
18. Lower the vehicle.