Fuel Filler Neck

This procedure covers removal and replacement of the fuel filler neck on a 2007 Ram 3500 with 5.9L Cummins diesel engine, including disconnection of hoses and mounting hardware.

Warnings

Tools required

Parts

• Fuel filler neck assembly × 1 — Use OEM specification
• Fuel filler neck grommet × 1 — Use OEM specification
• Hose clamps × 2 — Replace if corroded

Preparation

1. Park vehicle on level ground and set parking brake
2. Chock rear wheels for safety
3. Raise left rear of vehicle and support securely on jack stands
4. Remove left rear wheel for better access to filler neck area
5. Apply penetrating oil to all visible fasteners and hose clamps on the filler neck assembly
6. Allow penetrating oil to soak for 10-15 minutes

Procedure

1. 1

   Access the filler neck from wheel well
   From the wheel well area, locate the fuel filler neck assembly running from the fuel door down to the fuel tank. The filler neck is secured by a mounting bracket and connects to the fuel tank with a rubber hose and clamp.
2. 2

   Remove filler cap and inner components
   Open the fuel door and remove the fuel cap. Inside the filler neck opening, note any diesel fill restrictor or flapper present. If a restrictor is integral to the filler neck assembly, it will be replaced with the new assembly; otherwise note its orientation for reinstallation.
3. 3

   Disconnect vent hose at top
   If equipped, locate the vent/recirculation hose connected near the top of the filler neck assembly. Verify the clamp type (spring or worm-gear), then loosen it with hose clamp pliers or a flathead screwdriver, slide it away from the connection, and carefully twist and pull the vent hose off the filler neck nipple.
4. 4

   Remove filler neck mounting bracket
   Locate the mounting bracket that secures the filler neck to the body. This is typically held by fasteners on the body panel inside the wheel well area (commonly 10mm or Torx); verify the size and count against your vehicle before removal. Remove these bolts and set aside the bracket. Support the filler neck as you remove the last fastener.
5. 5

   Loosen lower hose clamp
   Position a drain pan beneath the lower connection where the filler neck meets the fuel tank. Use a flathead screwdriver or the appropriate hex/nut driver (verify the clamp head size, commonly 7mm or 8mm) to loosen the hose clamp at the fuel tank connection. Do not fully remove the clamp yet.
6. 6

   Remove filler neck from body grommet
   From inside the wheel well, grasp the filler neck firmly and pull it out of the rubber grommet in the body panel near the fuel door. This may require twisting and pulling with moderate force as the grommet creates a tight seal. Work the neck free carefully to avoid tearing the grommet.
7. 7

   Disconnect filler neck from fuel tank
   With the top of the filler neck free from the body, carefully lower it and disconnect it from the fuel tank inlet hose. Slide the loosened clamp completely off, then twist and pull the filler neck out of the rubber hose. Have shop towels ready as residual fuel will spill. Allow fuel to drain into the drain pan.
8. 8

   Inspect and clean connection points
   With the old filler neck removed, inspect the rubber grommet in the body panel for cracks or damage. Inspect the fuel tank inlet hose for cracks, splits, or deterioration. Clean the fuel tank inlet pipe and surrounding area with shop towels to remove debris and old fuel residue. Replace any damaged components.
9. 9

   Install new filler neck to fuel tank
   Position the new filler neck and insert the lower end into the fuel tank inlet hose approximately 2-3 inches. Ensure it is fully seated. Slide a new or cleaned hose clamp over the connection and position it about 1/2 inch from the end of the hose. Tighten the clamp securely with a flathead screwdriver or socket.
10. 10

    Install filler neck through body grommet
    Feed the upper portion of the filler neck through the rubber grommet in the body panel. Apply light pressure and twist the neck as needed to work it through the grommet until it seats flush with the body at the fuel door opening. Ensure the filler neck is properly aligned and the grommet seals completely around it.
11. 11

    Secure mounting bracket
    Position the mounting bracket around the filler neck and align it with the mounting holes in the body panel. Install the mounting fasteners (matching what was removed) and tighten securely, ensuring the filler neck is held firmly in place without stress or misalignment.
12. 12

    Reconnect vent hose
    Push the vent hose onto the nipple at the top of the filler neck assembly until it is fully seated. Slide the hose clamp into position about 1/2 inch from the end of the hose and tighten securely. Ensure the vent hose has no kinks or sharp bends that could restrict flow.
13. 13

    Reinstall restrictor and cap
    If equipped, reinstall the anti-siphon restrictor or plastic insert in the filler neck opening in the same orientation as removed. Install the fuel cap and close the fuel door.

Reassembly

1. Clean up any spilled fuel from the work area with shop towels
2. Reinstall the left rear wheel and torque lug nuts to specification
3. Lower the vehicle from jack stands
4. Properly dispose of fuel-soaked towels and materials according to local regulations

Verification

• Fill the fuel tank with at least 5 gallons of diesel fuel and monitor for leaks around all connections
• Check the filler neck area from the wheel well while fueling for any signs of dripping or seepage
• Verify the fuel cap seals properly and the check engine light does not illuminate (indicating EVAP system integrity)
• Check the vent hose connection for proper sealing by listening for air escaping during fueling
• Inspect under the vehicle after the first drive for any fuel drips or leaks

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