Catalytic Converter Replacement (LFA)

Catalytic Converter Replacement (LFA)

Removal Procedure





1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .
2. Remove the oil pan skid plate bolts and skid plate, if equipped.
3. Remove the transmission crossmember. Refer to Transmission Support Crossmember Replacement (4WD 2500 series) Transmission Support Crossmember Replacement (2WD 1500 series) Transmission Support Crossmember Replacement (2WD 2500 series) Transmission Support Crossmember Replacement (4WD 1500 series) .
4. Remove the heated oxygen (HO2S) sensors. Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 , Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 , Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 and Heated Oxygen Sensor Replacement - Bank 2 Sensor 2 .




5. Loosen the catalytic converter to muffler clamp bolt (1).




6. Remove the catalytic converter to exhaust manifold nuts (1).
7. Separate the catalytic converter assembly from the exhaust manifolds.
8. Remove the catalytic converter assembly from the exhaust muffler.
9. If replacing the catalytic converter assembly, perform the following steps, otherwise proceed to step 4 in the installation procedure.
10. Remove the exhaust seals (2 and 3).




11. Remove the HO2S's (1-5) from the catalytic converter assembly.



Installation Procedure

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 as exhaust component and if for any reason the sensor is to be reinstalled, the threads must have anti-seize compound applied before the reinstallation.







1. If replacing the catalytic converter assembly, perform the following steps, otherwise proceed to step 4.
2. If reinstalling the old sensors, coat the threads with anti-seize compound GM P/N 12377953, or equivalent.




3. Install the NEW exhaust seals (2 and 3) as required.
4. Install the catalytic converter assembly to the muffler.
5. Install the catalytic converter assembly to the exhaust manifolds.

Notice: Replacement components must be the correct part number for the application. Components requiring the use of the thread locking compound, lubricants, corrosion inhibitors, or sealants are identified in the service procedure. Some replacement components may come with these coatings already applied. Do not use these coatings on components unless specified. These coatings can affect the final torque, which may affect the operation of the component. Use the correct torque specification when installing components in order to avoid damage.

6. Install the catalytic converter to exhaust manifold nuts (1).

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





7. Install the muffler to catalytic converter bolt.

Tighten the nuts to 45 N.m (33 lb ft).





8. Install the transmission crossmember. Refer to Transmission Support Crossmember Replacement (4WD 2500 series) Transmission Support Crossmember Replacement (2WD 1500 series) Transmission Support Crossmember Replacement (2WD 2500 series) Transmission Support Crossmember Replacement (4WD 1500 series) .
9. Install the heated oxygen (HO2S) sensors. Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 , Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 , Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 and Heated Oxygen Sensor Replacement - Bank 2 Sensor 2 .
10. Position the oil pan skid plate and install the oil pan skid plate bolts, if equipped.

Tighten the bolts to 28 N.m (21 lb ft).

11. Lower the vehicle.