To replace the Catalytic Converter in vehicles with 4.8l, 5.3l, 6.0l or 6.2l engines operators must first support their vehicle in the air then remove all bolts from the oil pan skid plate including the plate if the vehicle contains one before moving to the transmission crossmember. Next disconnect the right front heated Oxygen Sensor (HO2S) electrical connector from the engine wiring harness before removing the right front connector position assurance (CPA) retainer. First disconnect the right rear ho2s electrical connector by removing its clip and then repeat this step for the left rear ho2s. Vehicles with 4l60-e/4l70-e automatic transmission need left front cpa retainer removal and left front ho2s electrical connector disconnection. The Catalytic Converter to
Muffler nuts need removal for 1500 series vehicles. Owners of 2500/3500 vehicles should remove Muffler to Catalytic Converter nuts. First remove nuts holding the Catalytic Converter assembly to the
Exhaust Manifold and Muffler before severing the assembly from these components. During an assembly replacement ensure you discard the exhaust seals and remove oxygen sensors from the assembly. Before sensor installation smooth the ho2s threads with gm p/n 12377953 anti-seize compound followed by attaching the ho2s to the Catalytic Converter assembly and securing it to 42 n.m (31 lb ft). Attach the Catalytic Converter assembly to the combination of Muffler and exhaust manifolds by torquing both manifold nuts to 50 n.m (37 lb ft) and installing new exhaust seals if needed. For all vehicles except 2500/3500 series reattach the ho2s and tighten the Catalytic Converter to Muffler nuts to 45 n.m (33 lb ft). During 1500 series installment torque the Muffler nuts with same force as the Catalytic Converter. Tell the electrical ho2s connectors to connect and reinstall the cpa retainers. Reinstallation of the transmission crossmember gets followed by positioning the oil pan skid plate before tightening all bolts to 28 n.m (21 lb ft) and lowering the vehicle.