GM Service Manual Online
For 1990-2009 cars only

Catalytic Converter Replacement Rear Wheel Drive

Removal Procedure

Caution: Always wear protective goggles and gloves when removing exhaust parts as falling rust and sharp edges from worn exhaust components could result in serious personal injury.

Caution: In order to avoid being burned, do not service the exhaust system while it is still hot. Service the system when it is cool.

An accumulation of dirt and corrosion may make removing exhaust components difficult. Applying a penetrating oil on the threads of the bolts may assist in the removal of these components.

  1. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
  2. Support the catalytic converter assembly.

  3. Object Number: 179017  Size: SH
  4. Remove the three oxygen sensor electrical connections and clips.

  5. Object Number: 84636  Size: SH
  6. Remove the nuts from the muffler flange bolts.

  7. Object Number: 179014  Size: SH
  8. Remove the nuts from the exhaust manifold studs (right side).
  9. Disconnect the collars from the exhaust manifold studs (right side).

  10. Object Number: 107424  Size: SH
  11. Remove the nuts from the exhaust manifold studs (left side).
  12. Disconnect the collars from the exhaust manifold studs (left side).

  13. Object Number: 84636  Size: SH
  14. Remove the catalytic converter assembly from the muffler assembly.
  15. Remove the catalytic converter assembly from the exhaust manifolds.
  16. Lower the front of the catalytic converter assembly.

  17. Object Number: 163865  Size: SH
  18. Remove the catalytic converter assembly from the hanger.
  19. Notice: Do not damage the oxygen sensors when removing the catalytic converter.

  20. Remove the catalytic converter assembly from the vehicle by rotating the assembly over the rear of the transmission crossmember.
  21. Remove the three oxygen sensors. Refer to Heated Oxygen Sensor Replacement in Engine Controls.

Installation Procedure

When installing exhaust components, inspect the exhaust system for proper alignment. Misaligned components commonly cause rattles, noise and vibrations in the exhaust system. During system alignment, leave all of the bolts or nuts loose, until all of the parts are properly aligned. After properly aligning the parts, tighten the bolts or nuts from the front to the rear.

In order to maintain the alignment of the exhaust system, replace any damaged exhaust system hangers, hanger brackets, and clamps.

Important: 

   • Replacement of exhaust system parts must be OEM standard to ensure that the vehicle operates as designed.
   • When exhaust system service requires removing and replacing an oxygen sensor, refer to Heated Oxygen Sensor Replacement in Engine Controls.
   • Always use new nuts when installing the exhaust pipe to the exhaust manifold.
   • Before installing the new nuts, clean the exhaust manifold stud threads with a wire brush.

  1. Install the three oxygen sensors to the catalytic converter assembly. Refer to Heated Oxygen Sensor Replacement in Engine Controls.

  2. Object Number: 163865  Size: SH
  3. Install the catalytic converter assembly to the hanger.

  4. Object Number: 107424  Size: SH
  5. Install the collars on the catalytic converter assembly to the exhaust manifold studs (left side).
  6. Loosely install the nuts onto the exhaust manifold studs (left side).

  7. Object Number: 179014  Size: SH
  8. Install the collars on the catalytic converter assembly to the exhaust manifold studs (right side).
  9. Loosely install the nuts onto the exhaust manifold studs (right side).

  10. Object Number: 84636  Size: SH
  11. Connect the catalytic converter assembly and the gasket to the muffler assembly.
  12. Loosely install the nuts.

  13. Object Number: 227399  Size: SH

    Notice: 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.

  14. Tighten the exhaust manifold nuts in proper sequence (1-6).
  15. Tighten

        • Tighten the catalytic converter assembly-to-exhaust manifold nuts to 53 N·m (39 lb ft).
        • Tighten the catalytic converter assembly-to-muffler assembly nuts to 40 N·m (30 lb ft).

    Object Number: 179017  Size: SH
  16. Install the three oxygen sensor electrical connections and clips.
  17. Remove the support from the catalytic converter assembly.
  18. Lower the vehicle.

Catalytic Converter Replacement Automatic Four Wheel Drive

Removal Procedure

Caution: Always wear protective goggles and gloves when removing exhaust parts as falling rust and sharp edges from worn exhaust components could result in serious personal injury.

Caution: In order to avoid being burned, do not service the exhaust system while it is still hot. Service the system when it is cool.

An accumulation of dirt and corrosion may make removing exhaust components difficult. Applying a penetrating oil on the threads of the bolts may assist in the removal of these components.

  1. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
  2. Support the catalytic converter assembly.

  3. Object Number: 179017  Size: SH
  4. Remove the three oxygen sensor electrical connections and clips.

  5. Object Number: 84636  Size: SH
  6. Remove the nuts from the muffler flange bolts.

  7. Object Number: 179014  Size: SH
  8. Remove the nuts from the exhaust manifold studs (right side).
  9. Disconnect the collars from the exhaust manifold studs (right side).

  10. Object Number: 107424  Size: SH
  11. Remove the nuts from the exhaust manifold studs (left hand).
  12. Disconnect the collars from the exhaust manifold studs (left side).

  13. Object Number: 72538  Size: SH
  14. Remove the catalytic converter assembly hanger from the transfer case.
  15. Remove the catalytic converter assembly hanger from the catalytic converter.
  16. Separate the catalytic converter assembly from the muffler assembly.
  17. Separate the catalytic converter assembly from the exhaust manifolds.
  18. Notice: Do not damage the oxygen sensors when removing the catalytic converter.

  19. Remove the catalytic converter assembly from the vehicle by doing the following:
  20. 13.1. Lower the rear of the catalytic converter assembly.
    13.2. Move the catalytic converter assembly toward the rear of the vehicle.
    13.3. Rotate and lower the catalytic converter assembly behind the transfer case support crossmember.
  21. Remove the oxygen sensors from the catalytic converter assembly. Refer to Heated Oxygen Sensor Replacement in Engine Controls.

Installation Procedure

Notice: Replacement of exhaust system parts must be OEM standard to ensure that the vehicle operates as designed.

When installing exhaust components, inspect the exhaust system for proper alignment. Misaligned components commonly cause rattles, noise and vibrations in the exhaust system. During system alignment, leave all of the bolts or nuts loose, until all of the parts are properly aligned. After properly aligning the parts, tighten the bolts or nuts from the front to the rear.

In order to maintain the alignment of the exhaust system, replace any damaged exhaust system hangers, hanger brackets, and clamps.

Important: 

   • Replacement of exhaust system parts must be OEM standard to ensure that the vehicle operates as designed.
   • When exhaust system service requires removing and replacing an oxygen sensor, refer to Heated Oxygen Sensor Replacement in Engine Controls.
   • Always use new nuts when installing the exhaust pipe to the exhaust manifold.
   • Before installing the new nuts, clean the exhaust manifold stud threads with a wire brush.

  1. Install the oxygen sensors to the catalytic converter assembly. Refer to Heated Oxygen Sensor Replacement in Engine Controls.
  2. Install the catalytic converter assembly by doing the following:
  3. 2.1. Raise the catalytic converter assembly into the vehicle, from behind the transfer case support crossmember.
    2.2. Rotate the catalytic converter assembly, while directing the left exhaust pipe between the torsion bar and the transmission.
    2.3. Move the catalytic converter assembly toward the front of the vehicle.

    Object Number: 107424  Size: SH
  4. Install the collars on the catalytic converter assembly to the exhaust manifold studs (left side). Loosely install the nuts onto the exhaust manifold studs (left side).

  5. Object Number: 179014  Size: SH
  6. Install the collars on the catalytic converter assembly to the exhaust manifold studs (right side). Loosely install the nuts onto the exhaust manifold studs (right side).

  7. Object Number: 84636  Size: SH
  8. Connect the catalytic converter assembly and gasket to the muffler assembly.
  9. Loosely install the nuts.

  10. Object Number: 72538  Size: SH
  11. Connect the catalytic converter assembly hanger to the catalytic converter assembly.
  12. Loosely install the catalytic converter assembly hanger to the transfer case.

  13. Object Number: 227399  Size: SH

    Notice: 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.

  14. Tighten the exhaust manifold nuts in proper sequence (1-6).
  15. Tighten

        • Tighten the catalytic converter assembly-to-exhaust manifold nuts to 53 N·m (39 lb ft).
        • Tighten the catalytic converter assembly hanger-to-transfer case bolts to 55 N·m (40 lb ft).
        • Tighten the catalytic converter assembly-to-muffler assembly nuts to 40 N·m (30 lb ft).

    Object Number: 179017  Size: SH
  16. Install the three oxygen sensor electrical connections and the clips.
  17. Remove the support from the catalytic converter assembly.
  18. Lower the vehicle.