Hello, You will need to remove the fuel tank to get to the pump. GM has a special tool to remove the metal retaining ring that holds the fuel pump module in the tank, but a hammer and chisel will do the same job if you are careful. But do be careful of the fuel lines and connections as they are plastic and break real easy. I will post the tank removal first and then post the pump removal from the tank. Thanks

Fuel Tank Replacement (Single Tank)

Removal Procedure

Important: Clean the fuel and evaporative emission (EVAP) connections and surrounding areas prior to disconnecting the lines in order to avoid possible system contamination.

1. Relieve the fuel system pressure.
2. Drain the fuel tank.
3. Disconnect the vent hose quick connect fitting from the fuel tank.
4. Disconnect the fuel feed and EVAP lines from the fuel tank lines.
5. Cap the fuel and EVAP lines in order to prevent possible fuel and/or EVAP system contamination.
   
   
   
6. Disconnect the EVAP lines from the EVAP canister.
   
   
   
7. Using an adjustable jack, support the fuel tank.

   Notice: Do not bend the fuel tank straps. Bending the fuel tank straps may damage the straps.

8. Remove the fuel tank strap bolts.
9. Remove the fuel tank straps.
10. With the aid of an assistant, carefully lower the rear of the fuel tank.
11. Slide the front of the tank away from the frame.
12. Lower the fuel tank slightly until the electrical connectors can be accessed.
    
    
    
13. Disengage the sending unit connector position assurance (CPA) retainer.
14. Disconnect the sending unit and fuel pressure sensor electrical connectors.
15. Completely lower the fuel tank.
16. With the aid of an assistant, Place the fuel tank in a suitable work area.
    
    
    
17. If necessary, open the clip on the fuel tank and remove the fuel feed and EVAP lines.
18. If necessary, remove the fuel sending unit.

Installation Procedure

1. If necessary, install the fuel sending unit.
2. If necessary, install the fuel feed and EVAP lines to the clip on the fuel tank. Close the clip.
   
   
   
3. Place the fuel tank onto a suitable jack.
4. With the aid of an assistant, partially raise the fuel tank.
5. Connect the fuel sender and fuel pressure sensor electrical connectors.
6. Engage the CPA retainer.
   
   
   
7. Completely raise the fuel tank.
8. Install the fuel tank straps.

   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.

9. Install the fuel tank strap bolts.
   

   Tighten
   Tighten the bolts to 40 N·m (30 lb ft).

10. Remove the adjustable jack from the fuel tank.
11. Connect the vent line quick connect fitting.
12. Install the fill hose to the fuel tank.
13. Tighten the fill hose clamp at the tank.
    

    Tighten
    Tighten the clamps to 2.5 N·m (22 lb in).

14. If necessary, tighten the fill pipe bracket bolts.
    

    Tighten
    Tighten the bolts to 12 N·m (106 lb in).

    
    
    
    
15. Remove the caps from the fuel and EVAP pipes.
16. Connect the EVAP lines to the EVAP canister.
    
    
    
17. Connect the fuel and EVAP lines to the fuel tank lines.
18. Lower the vehicle.
19. Refill the fuel tank.
20. Install the fuel fill cap.
21. Connect the negative battery cable.
22. Use the following procedure in order to inspect for leaks:
    1. Turn the ignition ON, with the engine OFF, for 2 seconds.
    2. Turn the ignition OFF for 10 seconds.
    3. Turn the ignition ON, with the engine OFF.
    4. Inspect for fuel leaks.

Fuel Sender Assembly Replacement (4.8L and 5.3L Engines)

J 45722 Fuel Sender Lock Ring Wrench

1. Remove the fuel tank.
2. Disconnect fuel and evaporative emission (EVAP) lines from the fuel tank module.

   Notice: Avoid damaging the lock ring. Use only J-45722 to prevent damage to the lock ring.

   Notice: Do Not handle the fuel sender assembly by the fuel pipes. The amount of leverage generated by handling the fuel pipes could damage the joints.

   Important: Do NOT use impact tools. Significant force will be required to release the lock ring. The use of a hammer and screwdriver is not recommended. Secure the fuel tank in order to prevent fuel tank rotation.

3. Use the J 45722 and a long breaker-bar in order to unlock the fuel sender lock ring.
4. Remove the cam lock ring.
   
   
   
5. Carefully lift the fuel tank module from the fuel tank, enough to access the quick connect fittings below the module cover.
6. Squeeze the quick connect fittings (1) in order to disengage them from the module cover.
7. Remove the fuel tank module from the fuel tank.
8. Remove and discard the fuel tank module seal.
   
   
   

   Important: Some lock rings were manufactured with "DO NOT REUSE" stamped into them. These lock rings may be reused if they are not damaged or warped.

   Important: Inspect the lock ring for damage due to improper removal or installation procedures. If damage is found, install a NEW lock ring.

   Important: Check the lock ring for flatness.

9. Place the lock ring on a flat surface. Measure the clearance between the lock ring and the flat surface using a feeler gage at 7 points.
10. If warpage is less than 0.41 mm (0.016 in), the lock ring does not require replacement.
11. If warpage is greater than 0.41 mm (0.016 in), the lock ring must be replaced.

1. Install the NEW fuel tank module seal onto the fuel tank.
2. Position the fuel tank module part way into the fuel tank.
3. Connect the quick connect fittings (1) to the module cover.
4. Install the fuel tank module into the fuel tank.
5. Place the cam lock ring into position.
   
   
   

   Important: Always replace the fuel sender seal when installing the fuel sender assembly. Replace the lock ring if necessary. DO NOT apply any type of lubrication in the seal groove.
   Ensure the lock ring is installed with the correct side facing upward. A correctly installed lock ring will only turn in a clockwise direction.

6. Rotate the cam lock ring clockwise using the J 45722 until fully seated.
7. Connect the fuel and EVAP lines to the fuel tank module.
8. Install the fuel tank.