Catalytic Converter: Service and Repair

Catalytic Converter Replacement (LL8) (4.2L)

Removal Procedure





1. Remove the heated oxygen sensors (H2OS). Refer to Heated Oxygen Sensor 1 Replacement and Heated Oxygen Sensor 2 Replacement .
2. Remove the transmission mount. Refer to Transmission Mount Replacement (4.2L) Transmission Mount Replacement (5.3L) .
3. Remove the catalytic converter to muffler nuts (1).




4. Remove the front 2 muffler insulators (3 and 4) from the muffler hangers.
5. Pull back and separate the muffler (2) flange studs from the catalytic converter flange.
6. Reposition and secure the muffler end out of the way.
7. Remove and discard the old exhaust gasket.




8. Remove the catalytic converter to exhaust manifold nuts (2).
9. Remove the catalytic converter (3) from the vehicle.
10. Remove and discard the old exhaust seal (1).




11. Remove the catalytic converter hanger (1) from the catalytic converter.



Installation Procedure





1. Install the catalytic converter hanger (1) to the catalytic converter.




2. Install a NEW exhaust seal (1) into the exhaust manifold.
3. Install the catalytic converter (3) to the vehicle.

Notice: Refer to Fastener Notice .

4. Install the catalytic converter to exhaust manifold nuts (2).

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





5. Insecure and position the muffler assembly.
6. Install a NEW exhaust gasket onto the muffler studs.
7. Pull back and install the muffler (2) flange studs to the catalytic converter flange.
8. Install the front 2 muffler insulators (3 and 4) to the muffler hangers.




9. Install the catalytic converter to muffler nuts (1).

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

10. Install the transmission mount. Refer to Transmission Mount Replacement (4.2L) Transmission Mount Replacement (5.3L) .
11. Install the H2OS. Refer to Heated Oxygen Sensor 1 Replacement and Heated Oxygen Sensor 2 Replacement .