Installation Procedure

Install the muffler assembly from the front of the vehicle by lifting over the rear axle. Due to the weight of the exhaust system it may take 2 persons.
Install the muffler assembly hanger pins to the exhaust hanger insulators.

Fig 1: Installing Muffler Assembly Hanger Pins To Exhaust Hanger Insulators
Courtesy of GENERAL MOTORS CORP.

CAUTION: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
If equipped with a 4.3L engine, install the retaining nuts and new gasket to the front of the muffler.
Tighten

Tighten the catalytic converter to muffler retaining nuts to 48 N.m (35 ft lbs).

Fig 2: Installing Catalytic Converter To Muffler Retaining Nuts (4.3L)
Courtesy of GENERAL MOTORS CORP.
If equipped with a 4.8L/4.3L/6.0L engine, install the right catalytic converter in the muffler.
Tighten

Tighten the clamp nut to 54 N.m (40 ft lbs).
Install a new gasket and the nuts retaining the left catalytic converter to the muffler flange.
Tighten
- Verify that the exhaust system is properly aligned and tighten the right catalytic converter clamp to 54 N.m (40 ft lbs).
- Tighten the catalytic converter to the muffler flange nuts to 48 N.m (35 ft lbs).
Lower the vehicle.

Fig 3: Installing Right & Left Catalytic Converter (4.8L/4.3L/6.0L)
Courtesy of GENERAL MOTORS CORP.