🔧 Gladiator - Fuel Pump Replacement

On your Gladiator, the fuel pump is part of an in-tank fuel pump module (pump + level sender). Replacing it usually requires lowering the fuel tank, swapping the module and seal, then reinstalling the tank and checking carefully for leaks.

Difficulty Level: Advanced | Estimated Time: 3-5 hours

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⚠️ Safety & Precautions

• Work outside or in a very well-ventilated area—fuel vapors are highly flammable.
• No smoking, no sparks, no hot lights; keep a fire extinguisher nearby.
• Let the exhaust cool completely before starting.
• Depressurize the fuel system before disconnecting any fuel lines.
• Disconnect the negative battery cable to reduce spark risk.
• Support the fuel tank with a jack before removing straps; it can drop suddenly.
• Use jack stands on the frame; never rely on a jack alone.

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🔧 Required Tools

You'll need the following tools for this repair:

• Safety glasses
• Nitrile gloves
• Fire extinguisher (Class B)
• Floor jack (rated 3-ton minimum)
• Jack stands (rated 3-ton minimum)
• Wheel chocks
• Socket set (8mm-18mm)
• Ratchet (3/8" drive)
• Ratchet (1/2" drive)
• Extension set (3"-12")
• Torque wrench (10-150 ft-lbs)
• Flat-blade screwdriver
• Trim clip removal tool
• Fuel line disconnect pick set
• Pliers
• Brass punch (non-sparking)
• Dead-blow hammer
• Fuel transfer pump (hand siphon)
• Drain pan (at least 2-gallon)
• Shop rags
• OBD2 scan tool

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Fuel pump module assembly - Qty: 1
• Fuel pump module tank seal (O-ring/gasket) - Qty: 1
• Fuel pump module lock ring - Qty: 1
• Dielectric grease - Qty: 1

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📋 Before You Begin

• Park on level ground, set the parking brake, and chock the wheels.
• Drive until the tank is as low as possible; a lighter tank is much safer to lower.
• Plan a clean workspace; dirt in the tank can damage the new pump.
• If you have stored trouble codes, note them with an OBD2 scan tool before disconnecting the battery.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Depressurize the fuel system

• Open the fuel door and loosen the gas cap to vent tank pressure.
• Use an OBD2 scan tool to check for fuel-related codes and save them (optional but helpful).
• Locate the fuel pump fuse/relay in the power distribution center and remove it using your fingers or pliers.
• Start the engine and let it run until it stalls. Crank for 2-3 seconds more to bleed off residual pressure.
• Turn the key OFF and reinstall the fuse/relay later during reassembly.

Step 2: Disconnect the battery

• Use a 10mm socket and ratchet (3/8" drive) to disconnect the negative battery cable and secure it so it can’t spring back.

Step 3: Raise and support the truck

• Lift the rear with a floor jack (rated 3-ton minimum) at the correct lift point.
• Set it down on jack stands (rated 3-ton minimum) under the frame.
• Give the truck a gentle push to confirm it’s stable before crawling underneath.

Step 4: Support the fuel tank

• Position the floor jack (rated 3-ton minimum) under the fuel tank with a piece of wood or a flat pad (if available) to spread the load.
• Raise the jack slightly so it just supports the tank.

Step 5: Remove any shields/skid plates blocking the tank

• Use a socket set (8mm-18mm), ratchet (1/2" drive), and extension set (3"-12") to remove the bolts holding any skid plate/shielding in the way.
• Set hardware aside in order so reassembly is easier.

Step 6: Disconnect EVAP and vent hoses

• Identify EVAP/vent hoses at the tank (these are vapor lines that help control fuel vapors).
• Use pliers to release any hose clamps, and use a flat-blade screwdriver or trim clip removal tool to gently free any plastic retainers.
• Label hoses with tape for easy return.

Step 7: Disconnect electrical connectors at the tank

• Unplug the fuel pump module connector using your hand and a trim clip removal tool if the locking tab is stubborn.
• Apply a tiny amount of dielectric grease during reassembly (later) to help prevent corrosion.

Step 8: Disconnect the fuel supply line(s)

• Place a drain pan (at least 2-gallon) and shop rags under the connection.
• Disconnect the quick-connect fuel line. A “quick-connect” is a push-on fitting with a locking tab; use a fuel line disconnect pick set to release the lock without breaking it.
• Cap/cover the open line ends with clean rags to keep dirt out.

Step 9: Lower the tank enough to access the top

• Remove the fuel tank strap bolts using a socket set (8mm-18mm) and ratchet (1/2" drive).
• Slowly lower the floor jack (rated 3-ton minimum) a few inches at a time while watching for any lines/wires still attached.
• If something gets tight, stop lowering and disconnect it before continuing.

Step 10: Clean the area around the fuel pump module

• Use shop rags to wipe dirt away from the top of the tank around the module.
• This helps prevent contamination from falling into the tank.

Step 11: Remove the fuel pump module lock ring

• The lock ring is the large ring that twists to lock the module into the tank opening.
• Use a brass punch (non-sparking) and dead-blow hammer to tap the lock ring counterclockwise until it releases.
• Lift the lock ring off and set it aside.

Step 12: Remove the fuel pump module

• Carefully lift the module straight up. Tilt as needed to clear the fuel level float arm.
• Let fuel drain from the module into the tank; keep the drain pan (at least 2-gallon) ready for drips.
• Remove the old tank seal (O-ring/gasket) with a flat-blade screwdriver carefully so you don’t scratch the sealing surface.

Step 13: Install the new seal and fuel pump module

• Install the new fuel pump module tank seal (O-ring/gasket) into the tank opening.
• Lower the new fuel pump module assembly into the tank, guiding the float arm in without forcing it.
• Align the module/index marks the same way the old one sat (it must seat fully and flat).

Step 14: Reinstall and tighten the lock ring

• Install the new fuel pump module lock ring.
• Use the brass punch (non-sparking) and dead-blow hammer to tap it clockwise until it is fully seated and locked.

Step 15: Raise the tank and reconnect lines

• Use the floor jack (rated 3-ton minimum) to raise the tank back into position.
• Reconnect fuel lines by pushing the quick-connect on until it clicks; gently tug to confirm it’s locked.
• Reconnect EVAP/vent hoses and reinstall retainers using pliers, flat-blade screwdriver, and trim clip removal tool as needed.
• Reconnect the electrical connector; apply a thin film of dielectric grease to the connector seal area (not on the terminals).

Step 16: Reinstall tank straps and shields

• Install tank straps and start bolts by hand to avoid cross-threading.
• Tighten strap bolts using a socket set (8mm-18mm) and torque wrench (10-150 ft-lbs).
• Torque to 54 Nm (40 ft-lbs) for the fuel tank strap bolts.
• Reinstall any skid plates/shields using a socket set (8mm-18mm), ratchet (1/2" drive), and torque wrench (10-150 ft-lbs).

Step 17: Lower the truck and reconnect the battery

• Raise slightly with the floor jack (rated 3-ton minimum), remove the jack stands (rated 3-ton minimum), and lower to the ground.
• Reconnect the negative battery cable using a 10mm socket and ratchet (3/8" drive).

Step 18: Prime the fuel system and check for leaks

• Turn key to ON (do not start) for 3-5 seconds, then OFF. Repeat 3-4 times to prime the pump.
• Start the engine and let it idle.
• Inspect under the truck for leaks at the fuel line connection and around the tank.

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✅ After Repair

• Use an OBD2 scan tool to clear any fuel/EVAP codes that appeared during the repair.
• Test drive for 10-15 minutes, then re-check for fuel smell or damp spots under the tank.
• If the fuel gauge reads wrong, recheck that the module seated correctly and the connector is fully locked.

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💰 DIY vs Shop Cost

Shop Cost: $900-$1,600 (parts + labor)

DIY Cost: $250-$650 (parts only)

You Save: $650-$950 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 3-5 hours.

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🎯 Ready to get started?

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