1500 Classic - Fuel Pump Replacement ⛽

On your 1500 Classic, the fuel pump is part of the fuel pump module inside the fuel tank. The correct procedure is to lower the tank, remove the module, and install a new one.

First, two quick questions so I can be exact:

• ✅ Are you working at home with just basic hand tools (no lift, just jack and stands)?
• ✅ Is your fuel tank close to full, or under half?

Answer briefly and then follow the guide below — I’ll assume basic tools and no lift unless you say otherwise.

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Safety First ⚠️

• 🛑 Work outside or in a very well-ventilated area — fuel vapors are flammable and harmful.
• 🛑 No smoking, no open flames, no grinding/welding nearby.
• 🛑 Disconnect the negative battery cable before touching fuel lines. This prevents sparks and accidental cranking.
• 🛑 Support the truck with jack stands, never rely only on a jack.
• 🛑 Fuel is heavy: 1 gallon ≈ 3.8 L ≈ 2.7 kg. A full tank is very heavy. Try to get the tank as empty as possible before starting.

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Tools & Supplies Needed 🧰

• 🔧 Floor jack and jack stands (to safely lift and support the truck).
• 🔧 Transmission jack or a wide wooden board on a floor jack to support the fuel tank.
• 🔧 Socket set:
  • Common sizes: 13mm, 15mm, 18mm sockets for tank straps and shields.
  • Ratchet and short extensions.
• 🔧 Torx / Allen bits if your skid plate or shields use them (varies by truck).
• 🔧 Fuel line quick-disconnect tools (small plastic tools that release the fuel line clips).
• 🔧 Flat-blade screwdriver and plastic trim tool (for clips and connectors).
• 🔧 Brass drift/punch and small hammer (for the pump lock ring). Brass is used because it doesn’t spark.
• 🧴 Brake cleaner (to clean dirt around the pump before opening the tank).
• 🧴 Shop rags and a small drain pan (to catch any fuel drips).
• 🧴 Safety glasses and fuel-resistant gloves.
• 🧴 New fuel pump module assembly (for 3.6L flex-fuel, 4WD, crew cab — match by year/model/engine).
• 🧴 New pump module seal/O-ring (usually included with the pump; always replace).

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Key Torque Specs 🔩

• 🧷 Fuel tank strap bolts: ~ 40–50 N·m (30–37 ft-lb) (Ram spec varies slightly by strap; tighten evenly and firmly, not “gorilla tight”).
• 🧷 Skid plate / shield bolts: typically 20–30 N·m (15–22 ft-lb).
• 🧷 Fuel pump lock ring: tightened until the ring aligns with the marks and fully seats the module; it’s a “clocked” ring, not a torque value.

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Step 1 – Depressurize the Fuel System ⬇️

• ⛽ Pull the fuel pump relay or fuse from the underhood fuse box.
  • Check the fuse box cover diagram for the fuel pump relay/fuse location.
• ⛽ Start the engine and let it run until it stalls. This uses up the pressure in the fuel lines.
• ⛽ Crank it again for a few seconds to make sure it won’t start.
• ⛽ Turn the key off and remove it.
• ⛽ Disconnect the negative battery cable (10mm) and secure it away from the terminal.

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Step 2 – Raise and Support the Truck 🛠️

• 🛞 Park on level ground, set the parking brake, and chock the front wheels (blocks behind tires).
• 🛞 Use the floor jack under the rear axle to lift the rear of the truck.
• 🛞 Place jack stands under the frame rails on both sides and gently lower the truck onto them.
• 🛞 Give the truck a shake to confirm it’s stable.

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Step 3 – Access the Fuel Tank (Shields & Hoses) 🔍

• 🛡️ If equipped, remove the fuel tank skid plate or shield:
  • Use the appropriate sockets (often 13mm or 15mm).
  • Set bolts and plate aside in order.
• 🛡️ Locate the fuel filler neck where it meets the tank:
  • Loosen the hose clamp (flat screwdriver or 8mm socket).
  • Gently twist and pull the filler hose off the tank neck.
• 🛡️ Disconnect any vent hoses and EVAP lines at the tank:
  • These often have plastic quick-connects; press the tabs and pull straight off.
  • Do not pry hard; if it doesn’t release, you may be pressing the wrong side.

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Step 4 – Support and Lower the Fuel Tank 🧱

• 📦 Place a transmission jack or floor jack with a wide board under the center of the tank to spread the load.
• 📦 Slightly raise the jack to just support the tank’s weight.
• 📦 Remove the fuel tank strap bolts (usually 15mm or 18mm):
  • There are typically two straps; remove bolts while the jack supports the tank.
• 📦 Slowly lower the tank a few inches, just enough to reach the top connections.
• 📦 Do not drop it fully yet — wiring and fuel lines are still attached.

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Step 5 – Disconnect Fuel Lines & Electrical Connectors 🔌

• 🔌 On top of the tank, locate the fuel pump module (round plastic top with lines and a connector).
• 🔌 Disconnect the electrical connector:
  • Press the locking tab and pull straight off.
• 🔌 Disconnect the fuel supply line and any return/EVAP lines:
  • Use the fuel line quick-disconnect tool to release the internal spring clip.
  • Slide the tool into the fitting, push the line in slightly, then pull it off.
  • Have a rag ready for small fuel drips.
• 🔌 Once all lines and connectors are free, lower the tank fully and slide it out from under the truck.

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Step 6 – Remove the Fuel Pump Module 🧽

• 🧽 Clean the area around the pump module with brake cleaner and rags so dirt doesn’t fall into the tank.
• 🧽 Note the orientation marks on the pump and tank (often arrows or notches). Take a photo for reference.
• 🧽 The pump is held by a lock ring:
  • Use a brass drift/punch and hammer.
  • Tap the ring counterclockwise to unlock it.
  • Do not use steel chisels; they can spark.
• 🧽 Lift the lock ring off and remove the old O-ring seal.
• 🧽 Carefully lift the pump module straight up:
  • Angle it slightly to clear the float arm and strainer.
  • Let excess fuel drain back into the tank.

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Step 7 – Install the New Fuel Pump Module 🆕

• 🆕 Wipe the tank sealing surface clean; it must be smooth and free of debris.
• 🆕 Install the new O-ring seal into the groove on the tank.
• 🆕 Position the new pump module:
  • Align it with the same orientation as the old one (use your photo/marks).
  • Carefully lower it into the tank, guiding the float and strainer.
• 🆕 Install the lock ring:
  • Place it over the pump and start it by hand.
  • Tap it clockwise with the brass drift until it fully seats and aligns with the original marks.

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Step 8 – Reinstall the Fuel Tank 🔁

• 🔁 Slide the tank back under the truck and position it on the jack.
• 🔁 Raise it slowly until you can reach the top connections.
• 🔁 Reconnect:
  • Electrical connector to the pump module.
  • Fuel supply line and any return/EVAP lines (push until you hear/feel a click).
• 🔁 Raise the tank fully into place.
• 🔁 Install the tank straps and bolts:
  • Snug both straps first, then torque to about 40–50 N·m (30–37 ft-lb).
• 🔁 Reconnect the filler neck hose and vent hoses:
  • Slide the hose fully onto the neck and tighten the clamp securely.
• 🔁 Reinstall any skid plates or shields and tighten their bolts (about 20–30 N·m).

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Step 9 – Reconnect Battery & Prime the System 🔄

• 🔋 Reinstall the fuel pump relay/fuse.
• 🔋 Reconnect the negative battery cable and tighten the 10mm nut.
• 🔋 Turn the key to ON (run) for 5 seconds (do not crank), then back to OFF. Repeat 3–4 times to prime the fuel system (build pressure).
• 🔋 Now crank the engine. It may crank a bit longer the first time, then should start and idle normally.
• 🔋 Check under the truck for any fuel leaks around the tank and lines.

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Step 10 – Final Checks ✅

• ✅ Clear any fuel smell by letting the truck run outside for a few minutes.
• ✅ Verify the fuel gauge reads reasonably (it may take a moment to stabilize).
• ✅ Take a short test drive and recheck for leaks afterward.

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Cost & Tips 💡

• 💡 A shop would typically charge 4–5 hours labor + parts for this job, which can be quite expensive. Doing it yourself saves a lot if you work carefully.
• 💡 If your tank is very full, consider driving until it’s near 1/4 before starting, or siphon some fuel out safely.
• 💡 Take photos at each step (hose routing, connectors, strap positions). They’re very helpful during reassembly.

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If you tell me how full your tank is and what tools you have (jack, stands, etc.), I can tailor this to your exact setup and help you pick the correct pump module part number for your 3.6L flex-fuel 4WD.

HowToo makes it easy: same-day/2-day shipping on every part, plus all the tools and specialty tools you need! You can view compatible fuel pump modules, quick-disconnect tools, jacks, and safety gear in the parts section and add them to your cart from there.