Catalytic Converter: Service and Repair

Catalytic Converter Replacement (8.1L Engines)

Removal Procedure

Caution: Refer to Exhaust.
Exhaust System Inspection Notice

Caution: Refer to Protective Goggles and Gloves Caution in Service and Precautions.
Protective Goggles and Glove Caution

1. Raise and suitably support the vehicle. Refer to Vehicle Lifting.
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. Remove the muffler.





8. Disconnect the Connector Position Assurance (CPA) retainers.
9. Disconnect the oxygen sensor electrical connectors (1, 2).





10. Loosen the right exhaust manifold pipe nuts.
11. Remove the left exhaust manifold pipe nuts.
12. Using the transmission jack, lower the transmission slightly.





13. Remove the catalytic converter.
14. Slide the catalytic converter hanger out of the exhaust pipe hanger bracket.





15. If equipped with a 6.0L engine, with regular production option (RPO) Y91, remove the catalytic converter.
16. Slide the catalytic converter hanger out of the exhaust pipe hanger bracket.





17. Remove the oxygen sensors if the catalytic converter is to be replaced.

Installation Procedure






Notice: Refer to Fastener Notice in Service and Precautions.
Fastener Notice


1. If the catalytic converter was replaced, perform the following:
1.1. Apply anti-seize compound GM P/N 12377953 or equivalent to the threads of the old oxygen sensors.
1.2. Install the oxygen sensors.
Tighten the sensors to 42 Nm (31 ft. lbs.).





2. Install the catalytic converter.
Slide the catalytic converter hanger into the exhaust pipe hanger bracket.





3. Install a NEW exhaust seal to the exhaust manifold.
4. Install the catalytic converter.
Slide the catalytic converter hanger into the exhaust pipe hanger bracket.





5. Install the left exhaust manifold pipe nuts.
6. Tighten the right exhaust manifold pipe nuts.
Tighten the nuts to 50 Nm (39 ft. lbs.).

7. Using the transmission jack, raise the transmission slightly.





8. Connect the oxygen sensor electrical connectors (1, 2).
9. Connect the CPA retainers.
10. Install the muffler.





12. Install the transmission support crossmember.
13. Install the transmission support crossmember bolts.
Tighten the bolts to 95 Nm (70 ft. lbs.).





14. Lower the transmission onto the transmission support.
15. Install the transmission mount to transmission support nuts.
Tighten the nuts to 40 Nm (30 ft. lbs.).
16. Remove the support from the transmission.
17. Lower the vehicle.