GM Service Manual Online
For 1990-2009 cars only

Exhaust Crossover Pipe Replacement V8

Removal Procedure

    Warning: Refer to Exhaust Service Warning in the Preface section.

    Warning: Refer to Protective Goggles and Glove Warning in the Preface section.

  1. Ignition OFF.
  2. Warning: Refer to Battery Disconnect Warning in the Preface section.

  3. Disconnect the battery negative cable. Refer to Battery Negative Cable Disconnection and Connection.
  4. Danger: To avoid any vehicle damage, serious personal injury or death when major components are removed from the vehicle and the vehicle is supported by a hoist, support the vehicle with jack stands at the opposite end from which the components are being removed and strap the vehicle to the hoist.

  5. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle.
  6. Remove the right post-catalytic converter heated oxygen sensor (HO2S). Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 2.
  7. Remove the left post-catalytic converter HO2S. Refer to Heated Oxygen Sensor Replacement - Bank 2 Sensor 2.
  8. Support the exhaust system using a suitable jack.

  9. Object Number: 1947042  Size: SH

    Note: The exhaust crossover pipe assembly to left catalytic converter retaining nuts (3) are single use parts. They must be discarded after removal.

  10. Remove the exhaust crossover pipe assembly to left catalytic converter retaining nuts (3).
  11. Discard the nuts.


    Object Number: 1947044  Size: SH

    Note: The exhaust crossover pipe assembly to right catalytic converter retaining nuts (3) are single use parts. They must be discarded after removal.

  12. Remove the exhaust crossover pipe assembly to right catalytic converter retaining nuts (3).
  13. Discard the nuts.

  14. Separate the exhaust crossover pipe assembly (2) from the catalytic converter assemblies.

  15. Object Number: 1949712  Size: SH
  16. Remove the transmission tunnel cross-brace to body retaining bolts (2).
  17. Remove the transmission tunnel cross-brace (1).

  18. Object Number: 1947045  Size: SH
  19. Remove the exhaust crossover pipe assembly to left rear muffler retaining bolts (3).
  20. Disconnect the left rear muffler (1) from the exhaust crossover pipe assembly (2).

  21. Object Number: 1949729  Size: SH
  22. Remove the exhaust crossover pipe assembly to right rear muffler retaining bolts (3).
  23. Disconnect the right rear muffler (1) from the exhaust crossover pipe assembly (2).

  24. Object Number: 1947040  Size: SH
  25. Detach the exhaust system (2) by removing the front insulator hangers (1).

  26. Object Number: 1947047  Size: SH
  27. Remove the centre insulator hanger bracket to differential retaining nut (1).
  28. Detach the exhaust crossover pipe assembly from the centre insulator hanger to differential retaining stud (1).
  29. With the aid of an assistant or using a suitable jack; carefully lower the exhaust system from the vehicle.

Installation Procedure

    Caution: Refer to Exhaust System Inspection Caution in the Preface section.

  1. Clean all threads and flange faces of the exhaust crossover pipe assembly.
  2. Replace the catalytic converter to exhaust crossover pipe assembly flange gaskets.
  3. With the aid of an assistant or using a suitable jack; position the exhaust crossover pipe assembly to the vehicle.

  4. Object Number: 1947047  Size: SH
  5. Align the exhaust crossover pipe assembly to the centre insulator hanger bracket to differential retaining stud (1).

  6. Object Number: 1947040  Size: SH
  7. Attach the exhaust crossover pipe assembly (2) to the transmission support by installing the front insulator hangers (1), if fitted.
  8. Caution: Refer to Fastener Caution in the Preface section.


    Object Number: 1947047  Size: SH
  9. Install the centre insulator hanger bracket to differential retaining nut (1) and tighten to 45 N·m (33 lb ft).

  10. Object Number: 1949712  Size: SH
  11. Install the transmission tunnel cross-brace (1).
  12. Install the transmission tunnel cross-brace to body retaining bolts (2) and tighten to 12 N·m (9 lb ft).

  13. Object Number: 1947044  Size: SH
  14. Align the exhaust crossover pipe assembly (2) to the right catalytic converter (1).
  15. Install the exhaust crossover pipe assembly to right catalytic converter retaining nuts (3) and tighten to 40 N·m (30 lb ft).

  16. Object Number: 1947042  Size: SH
  17. Align the exhaust crossover pipe assembly (2) to the left catalytic converter (1).
  18. Install the exhaust crossover pipe assembly to left catalytic converter retaining nuts (3) and tighten to 40 N·m (30 lb ft).

  19. Object Number: 1949729  Size: SH
  20. Connect the right rear muffler (1) to the exhaust crossover pipe assembly (2).
  21. Install the exhaust crossover pipe assembly to right rear muffler retaining bolts (3) and tighten to 45 N·m (33 lb ft).

  22. Object Number: 1947045  Size: SH
  23. Connect the left rear muffler (1) to the exhaust crossover pipe assembly (2).
  24. Install the exhaust crossover pipe assembly to left rear muffler retaining bolts (3) and tighten to 45 N·m (33 lb ft).
  25. Install the right post-catalytic converter heated oxygen sensor (HO2S). Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 2.
  26. Install the left post-catalytic converter HO2S. Refer to Heated Oxygen Sensor Replacement - Bank 2 Sensor 2.
  27. Make sure that the exhaust system is clear of all other components and chassis. If the exhaust system is not clear of all the other components loosen all retaining nuts and re-align. Refer to Exhaust System Alignment.
  28. Lower the vehicle.
  29. Connect the battery negative cable. Refer to Battery Negative Cable Disconnection and Connection .

Exhaust Crossover Pipe Replacement V6

Removal Procedure

    Warning: Refer to Exhaust Service Warning in the Preface section.

    Warning: Refer to Protective Goggles and Glove Warning in the Preface section.

  1. Ignition OFF.
  2. Warning: Refer to Battery Disconnect Warning in the Preface section.

  3. Disconnect the battery negative cable. Refer to Battery Negative Cable Disconnection and Connection.
  4. Danger: To avoid any vehicle damage, serious personal injury or death when major components are removed from the vehicle and the vehicle is supported by a hoist, support the vehicle with jack stands at the opposite end from which the components are being removed and strap the vehicle to the hoist.

  5. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle.
  6. Remove the right post-catalytic converter heated oxygen sensor (HO2S). Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 2.
  7. Remove the left post-catalytic converter HO2S. Refer to Heated Oxygen Sensor Replacement - Bank 2 Sensor 2 .

  8. Object Number: 2179318  Size: SH

    Note: The exhaust crossover pipe assembly to catalytic converter retaining nuts (3) are single use parts. They must be discarded after removal.

  9. Remove exhaust crossover pipe assembly to catalytic converter retaining nuts (3).
  10. Discard the nuts.

  11. Separate the exhaust crossover pipe assembly (2) from the catalytic converter assemblies (1).

  12. Object Number: 1949712  Size: SH
  13. Remove the transmission tunnel cross-brace to body retaining bolts (2).
  14. Remove the transmission tunnel cross-brace (1).
  15. Support the exhaust system with a suitable jack.

  16. Object Number: 1947045  Size: SH
  17. Remove the exhaust crossover pipe assembly to rear muffler retaining bolts (3)
  18. Disconnect the rear left muffler (1) from the exhaust crossover pipe assembly (2)

  19. Object Number: 1949729  Size: SH
  20. Remove the exhaust crossover pipe assembly to rear muffler retaining bolts (2)
  21. Disconnect the rear right muffler (1) from the exhaust crossover pipe assembly (3)

  22. Object Number: 1947047  Size: SH
  23. Remove the centre insulator hanger bracket to differential retaining nut (1).
  24. Detach the exhaust crossover pipe assembly.
  25. Carefully lower the exhaust crossover pipe assembly from the vehicle.

Installation Procedure

    Caution: Refer to Exhaust System Inspection Caution in the Preface section.

  1. Clean all threads and flange faces of the exhaust crossover pipe assembly.
  2. Replace the catalytic converter to intermediate pipe flange gaskets.
  3. Position the exhaust crossover pipe assembly to the vehicle using a suitable jack.

  4. Object Number: 1947047  Size: SH
  5. Align the exhaust system to the centre insulator hanger bracket to differential retaining bolt.
  6. Caution: Refer to Fastener Caution in the Preface section.

  7. Install the centre insulator hanger bracket to differential retaining nut (1) and tighten to 45 N·m (33 lb ft).

  8. Object Number: 1947045  Size: SH
  9. Connect the left rear muffler (1) to the exhaust crossover pipe assembly (2).
  10. Install the exhaust crossover pipe assembly to left rear muffler retaining bolts (3) and tighten to 45 N·m (33 lb ft).

  11. Object Number: 1949729  Size: SH
  12. Connect the right rear muffler (1) to the exhaust crossover pipe assembly (3).
  13. Install the exhaust crossover pipe assembly to right rear muffler retaining bolts (3) and tighten to 45 N·m (33 lb ft).

  14. Object Number: 1949712  Size: SH
  15. Install the transmission tunnel cross-brace (1).
  16. Install the transmission tunnel cross-brace to body retaining bolts (2) and tighten to 12 N·m (9 lb ft).

  17. Object Number: 2179318  Size: SH
  18. Align the catalytic converter assemblies (1) to the exhaust crossover pipe assembly (2).
  19. Install the NEW exhaust crossover pipe assembly to catalytic converter retaining nuts (3) and tighten to 40 N·m (30 lb ft).
  20. Make sure that the exhaust system is clear of all other components and chassis. If the exhaust system is not clear of all the other components loosen all retaining nuts and re-align. Refer to Exhaust System Alignment.
  21. Install the right post-catalytic converter HO2S. Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 2.
  22. Install the left post-catalytic converter HO2S. Refer to Heated Oxygen Sensor Replacement - Bank 2 Sensor 2 .
  23. Lower the vehicle.
  24. Connect the battery negative cable. Refer to Battery Negative Cable Disconnection and Connection .