GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2007 🢒 Avalanche - 4WD 🢒 Engine 🢒 Engine Exhaust 🢒 Exhaust Seal Replacement

Exhaust Seal Replacement 1500

Removal Procedure

    Object Number: 1698082 Size: SH
  1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .
  2. Remove the oil pan skid plate bolts and skid plate, if equipped.

    3. Object Number: 1704006 Size: SH
  3. Remove the right front connector position assurance (CPA) retainer (2).
  4. Disconnect the right front heated oxygen sensor (HO2S) electrical connector from the engine wiring harness electrical connector (1).
  5. Remove the right rear CPA retainer (4).
  6. Disconnect the engine wiring harness electrical connector (3) from the right rear HO2S electrical connector.
  7. Remove the right rear HO2S electrical connector clip from the engine harness clip (5).

    8. Object Number: 1704005 Size: SH
  8. Remove the left rear CPA retainer (1).
  9. Disconnect the left rear HO2S electrical connector from the engine wiring harness electrical connector (3).

    10. Object Number: 1704004 Size: SH
  10. For vehicles equipped with a 4L60-E/4L70-E automatic transmission perform the following steps, for vehicles equipped with a 6L80-E automatic transmission proceed to step 14.
  11. Remove the left front CPA retainer.
  12. Disconnect the engine wiring harness electrical connector (2) from the left front HO2S.
  13. Remove the left front HO2S electrical connector clip (1) from the fuel line clip.

    14. Object Number: 1704002 Size: SH
  14. Remove the left front CPA retainer (2).
  15. Remove the engine wiring harness electrical connector clip (1) from the fuel line clip.
  16. Disconnect the engine wiring harness electrical connector (3) from the left front HO2S.
  17. Support the catalytic converter assembly with a suitable adjustable jack.
  18. Remove the HO2S. Refer to Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 .

    19. Object Number: 1708626 Size: SH
  19. Remove the catalytic converter to exhaust manifold nuts (1).
  20. Separate the catalytic converter assembly from the exhaust manifolds.
  21. Lower the catalytic converter assembly using the adjustable jack.
  22. Remove the exhaust seal (2 or 3) as required.

Installation Procedure

    Object Number: 1708626 Size: SH
  1. Install the NEW exhaust seal (2 or 3) as required.
  2. Raise the catalytic converter assembly into place using the adjustable jack.
  3. Install the catalytic converter assembly to the exhaust manifolds.

    4. Notice: Refer to Fastener Notice in the Preface section.

  4. Install the catalytic converter to exhaust manifold nuts (1).

    5. Tighten
    Tighten the nuts to 50 N·m (37 lb ft).

  5. Remove the adjustable jack from the catalytic converter assembly.
  6. Install the HO2S. Refer to Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 .

    7. Object Number: 1704004 Size: SH
  7. For vehicles equipped with a 4L60-E/4L70-E automatic transmission perform the following steps, for vehicles equipped with a 6L80-E automatic transmission proceed to step 10.
  8. Install the HO2S electrical connector clip (1) to the fuel line clip.
  9. Connect the engine wiring harness electrical connector (2) to the HO2S.
  10. Install the CPA retainer.

    11. Object Number: 1704002 Size: SH
  11. Connect the engine wiring harness electrical connector (3) to the HO2S.
  12. Install the engine wiring harness electrical connector clip (1) to the fuel line clip.
  13. Install the CPA retainer (2).

    14. Object Number: 1704005 Size: SH
  14. Connect the left rear HO2S electrical connector to the engine wiring harness electrical connector (3).
  15. Install the left rear CPA retainer (1).

    16. Object Number: 1704006 Size: SH
  16. Install the right rear HO2S electrical connector clip to the engine harness clip (5).
  17. Connect the engine wiring harness electrical connector (3) to the right rear HO2S electrical connector.
  18. Install the right rear CPA retainer (4).
  19. Connect the right front HO2S electrical connector to the engine wiring harness electrical connector (1).
  20. Install the right front CPA retainer (2).

    21. Object Number: 1698082 Size: SH
  21. Position the oil pan skid plate and install the oil pan skid plate bolts, if equipped.

    22. Tighten
    Tighten the bolts to 28 N·m (21 lb ft).

  22. Lower the vehicle.

Exhaust Seal Replacement 2500

Removal Procedure

    Object Number: 1698083 Size: SH
  1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .
  2. Loosen the 2 rear oil pan skid plate bolts, remove the 2 front oil pad skid plate bolts and skid plate, if equipped.

    3. Object Number: 1704011 Size: SH
  3. Remove the right front connector position assurance (CPA) retainer (5).
  4. Disconnect the right front heated oxygen sensor (HO2S) electrical connector from the engine wiring harness electrical connector (1).
  5. Remove the right rear CPA retainer (3).
  6. Disconnect the engine wiring harness electrical connector (2) from the right rear HO2S electrical connector.
  7. Remove the right rear HO2S electrical connector clip from the engine harness clip (4).

    8. Object Number: 1704005 Size: SH
  8. Remove the left rear CPA retainer (1).
  9. Disconnect the left rear HO2S electrical connector from the engine wiring harness electrical connector (3).

    10. Object Number: 1704010 Size: SH
  10. Remove the left front CPA retainer (2).
  11. Disconnect the left front HO2S electrical connector (2) from the engine wiring harness electrical connector (3).

    12. Object Number: 1708691 Size: SH
  12. Support the catalytic converter assemblies with suitable adjustable jacks.
  13. Remove the exhaust pipe hanger bracket bolts.

    14. Object Number: 1708627 Size: SH
  14. Remove the catalytic converter to exhaust manifold nuts (2).
  15. Separate the catalytic converter assemblies from the exhaust manifolds.
  16. Lower the catalytic converter assemblies using the adjustable jacks.
  17. Remove the exhaust seal(s) (1) as required.

Installation Procedure

    Object Number: 1708627 Size: SH
  1. Install the NEW exhaust seal(s) (1) as required.
  2. Raise the catalytic converter assemblies into place using the adjustable jacks.
  3. Install the catalytic converter assemblies to the exhaust manifolds.

    4. Notice: Refer to Fastener Notice in the Preface section.

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

    5. Tighten
    Tighten the nuts to 50 N·m (37 lb ft).


    Object Number: 1708691 Size: SH
  5. Position the exhaust pipe hanger bracket to the transmission.
  6. Install the exhaust pipe hanger bracket bolts.

    7. Tighten
    Tighten the bolts to 25 N·m (18 lb ft).

  7. Remove the supports from the catalytic converter assemblies.

    8. Object Number: 1704010 Size: SH
  8. Connect the left front HO2S electrical connector (2) to the engine wiring harness electrical connector (3).
  9. Install the left front CPA retainer (2).

    10. Object Number: 1704005 Size: SH
  10. Connect the left rear HO2S electrical connector to the engine wiring harness electrical connector (3).
  11. Install the left rear CPA retainer (1).

    12. Object Number: 1704011 Size: SH
  12. Install the right rear HO2S electrical connector clip to the engine harness clip (4).
  13. Connect the engine wiring harness electrical connector (2) to the right rear HO2S electrical connector.
  14. Install the right rear CPA retainer (3).
  15. Connect the right front HO2S electrical connector to the engine wiring harness electrical connector (1).
  16. Install the right front CPA retainer (5).

    17. Object Number: 1698083 Size: SH
  17. Position the oil pan skid plate and tighten until snug the 2 rear oil pan skid plate bolts, install the 2 front oil pan skid plate bolts, if equipped.

    18. Tighten
    Tighten the bolts to 28 N·m (21 lb ft).

  18. Lower the vehicle.