Fuel Tank

This procedure covers the complete removal and installation of the fuel tank on a 2007 Ram 3500 with 5.9L Cummins diesel engine and 4WD.

Warnings

Tools required

Parts

• Fuel tank strap hardware kit (if corroded) × 1 — Use OEM specification
• Fuel tank sending unit gasket/seal × 1 — Use OEM specification
• Fuel filler neck grommet × 1 — Use OEM specification
• Vent hose clamps × 2 — Use OEM specification

Preparation

1. Park vehicle on level ground outdoors or in well-ventilated shop area away from ignition sources
2. Disconnect both negative battery cables to eliminate all electrical sources
3. Relieve fuel system pressure by loosening fuel cap slowly
4. If tank is more than 1/4 full, use approved fuel transfer pump to drain diesel into approved storage containers through filler neck or by disconnecting supply line
5. Raise vehicle on lift or securely support on jack stands rated for vehicle weight at frame rails - vehicle must be level
6. Allow exhaust system to cool completely (minimum 2 hours after engine operation)
7. Spray all fuel line fittings, tank strap bolts, and filler neck hardware with penetrating oil and allow to soak 15-30 minutes

Procedure

1. 1

   Disconnect fuel filler neck and vent lines
   Locate the fuel filler neck on driver side behind cab. Remove the hose clamp securing filler neck to tank using appropriate socket or screwdriver. Carefully twist and pull filler neck free from tank - expect residual fuel spillage. Locate vent line connection at top of tank and remove clamp, then disconnect vent hose. Cap or plug openings to prevent debris entry.
   ⚠Residual fuel will drain from filler neck - position drain pan to catch spillage.
2. 2

   Disconnect electrical connectors
   Locate the fuel tank sending unit electrical connector on top of tank near driver side. Press release tab and carefully disconnect connector. On some configurations, an in-tank transfer/lift pump electrical connector may also be present on the sender module - disconnect if equipped. Verify actual connectors present for this vehicle. Clean connections with electrical contact cleaner if corrosion is present.
   ⚠Connector lock tabs are brittle on older vehicles - use care to avoid breaking.
3. 3

   Disconnect fuel supply and return lines
   Locate fuel supply line (larger diameter) and return line running from tank forward to engine. These are quick-disconnect fittings on this model. Use appropriate fuel line disconnect tool to release locking mechanism on each fitting. Press tool onto fitting and pull line away from tank connection. Plug all open fuel line ends with appropriate caps to prevent contamination and fuel spillage. Position drain pan beneath work area.
   ⚠️Fuel under residual pressure may spray when lines are disconnected. Wear safety goggles and fuel-resistant gloves.
4. 4

   Position support for fuel tank
   Position transmission jack or fuel tank adapter jack under center of fuel tank. Raise jack until it just contacts tank bottom - do NOT lift tank yet. Secure tank to jack with retaining straps or chain to prevent tank from slipping when straps are released. Ensure jack is stable and centered under tank mass. Jack must be rated for at least 500 pounds and properly centered.
   ⚠️Even a partially drained tank is extremely heavy. Jack must be rated for at least 300 pounds and properly centered.
5. 5

   Remove front tank strap
   Locate the front fuel tank strap (closest to cab). The strap is secured with bolts at each end that thread into frame mounts. While supporting tank with jack, remove the driver side strap bolt first using appropriate socket and ratchet. Then remove passenger side bolt. Carefully lower and swing front strap down and away from tank. Inspect strap for cracks or severe corrosion - replace if damaged.
   ⚠Strap may be seized in mount brackets - do not force bolts as frame threads can strip. Apply additional penetrating oil if needed.
6. 6

   Remove rear tank strap
   Locate the rear fuel tank strap. Remove the driver side strap bolt first, then passenger side bolt using appropriate socket and ratchet. Carefully lower and swing rear strap down and away from tank. Tank is now supported only by jack - ensure jack is stable before proceeding.
   ⚠️Tank is now held only by jack - verify stable support before continuing. Have assistant nearby if possible.
7. 7

   Lower and remove fuel tank
   Slowly and carefully lower the transmission jack, monitoring that tank remains stable and centered on jack platform. Lower approximately 12 inches to clear frame rails. Verify no fuel lines, electrical wires, or vent hoses are still connected - if any connections remain, raise tank slightly and disconnect. Once clear, continue lowering tank to ground. Roll jack and tank assembly out from under vehicle to safe work area.
   ⚠Tank may hang up on crossmember or exhaust components - guide tank as needed while lowering.
8. 8

   Remove sending unit if servicing tank
   If replacing tank or servicing sending unit, clean top of tank thoroughly around sending unit ring. Note orientation of sending unit for reinstallation. Use large slip-joint pliers or fuel sending unit wrench to turn locking ring counterclockwise. Remove locking ring, then carefully lift sending unit assembly out of tank at an angle to clear fuel level float arm. Remove and inspect gasket/seal - replace if damaged, compressed, or deteriorated.
   ⚠Sending unit float arm extends down into tank - remove at angle to avoid bending arm.
9. 9

   Inspect and clean tank mounting area
   Inspect frame rails and tank strap mounting points for corrosion, damage, or deterioration. Wire brush all mounting surfaces clean. Inspect fuel tank shield (if equipped) for damage and secure mounting. Check condition of tank straps - replace if cracked, significantly rusted, or bent. Inspect rubber isolators between tank and straps - replace if compressed or deteriorated.
10. 10

    Install sending unit in tank
    If sending unit was removed, install new gasket/seal on tank opening. Carefully insert sending unit assembly into tank at angle to clear float arm, then rotate to proper orientation matching removal position. Install locking ring and tighten clockwise by hand, then use slip-joint pliers or sending unit wrench to firmly tighten ring - ensure gasket is evenly compressed around entire perimeter.
11. 11

    Raise tank into position
    Position tank on transmission jack and secure with straps or chain. Roll jack assembly under vehicle, centering tank beneath mounting location. Slowly raise tank toward frame, guiding tank to align with strap mounting points. Raise until tank is approximately 1 inch from fully seated position against frame isolators. Do not fully seat tank yet - leave room to work with straps.
12. 12

    Install rear tank strap
    Swing rear tank strap up and position over tank. Align strap ends with frame mounting holes. Start both strap bolts by hand, threading several turns to ensure proper thread engagement. Do not fully tighten - leave straps slightly loose to allow tank positioning adjustment.
    ⚠Cross-threading frame bolts will damage mounting threads requiring expensive repair. Ensure bolts thread smoothly by hand before using tools.
13. 13

    Install front tank strap and secure tank
    Swing front tank strap up and position over tank. Align strap ends with frame mounting holes and start both bolts by hand. Once all four strap bolts are hand-started, raise jack to fully seat tank against frame isolators. Tighten all four strap bolts in progressive alternating pattern (rear driver, front passenger, rear passenger, front driver) to draw tank evenly into position. Tighten bolts firmly to the factory-specified torque. Do not rely on a generic value—verify the exact fuel tank strap bolt torque in the Mopar service manual for this specific vehicle before final tightening. Remove jack support once straps are secured.
14. 14

    Reconnect fuel lines
    Remove plugs/caps from fuel supply and return line connections. Inspect quick-connect fittings for damage or debris - clean if needed. Push each fuel line firmly onto tank connection until distinct click is heard/felt indicating locking mechanism has engaged. Pull back on each line to verify secure connection - line should not separate with moderate pull force.
15. 15

    Reconnect electrical and complete installation
    Reconnect fuel tank sending unit electrical connector - press together until lock tab clicks. Reconnect fuel heater connector if equipped. Install vent hose onto tank connection and secure with new clamp. Install fuel filler neck into tank opening, rotate to proper position, and secure with new clamp - tighten clamp firmly to prevent fuel leaks. Verify all connections are complete and secure.

Reassembly

1. Double-check all fuel line connections are fully seated and locked
2. Verify fuel filler neck and vent hose clamps are tight
3. Ensure no tools or parts have been left on top of tank or frame
4. Verify tank straps are evenly tightened and tank is stable
5. Reconnect both negative battery cables

Verification

• Lower vehicle to ground
• Add 5 gallons of diesel fuel through filler neck
• Inspect entire tank area, all connections, straps, and filler neck for fuel leaks
• Turn ignition to ON position (do not start) and listen for fuel pump operation (if electric lift pump equipped)
• Start engine and allow to idle - monitor for fuel leaks at all connections
• Check fuel gauge operation shows approximately 1/8 full or expected level based on fuel added
• With engine running, inspect entire tank perimeter and all connections for active leaks
• After test drive, re-inspect all connections for seepage or leaks before returning vehicle to service

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