This procedure covers removal and replacement of the direct-fit catalytic converter on a 2014 Ram 2500 with the 6.7L Cummins diesel engine, including proper handling of oxygen sensors and exhaust components.

Warnings

Tools required

Parts

• Direct-fit catalytic converter assembly × 1 — Use OEM specification or EPA-compliant aftermarket
• Exhaust flange gaskets × 2 — Use OEM specification
• Exhaust flange bolts/nuts (if corroded) × 1 — M10x1.5 or M12x1.75 depending on location

Preparation

1. Park vehicle on level surface and set parking brake. Place wheel chocks behind rear wheels.
2. Allow exhaust system to cool completely (minimum 1 hour after last engine operation).
3. Apply penetrating oil to all exhaust flange bolts, hanger bolts, and oxygen sensor threads. Allow to soak for 15-30 minutes.
4. Raise vehicle using floor jack and support securely on jack stands at frame rails. Ensure adequate working clearance (minimum 24 inches).
5. Locate catalytic converter assembly between turbocharger outlet and DPF inlet. Identify upstream and downstream oxygen sensors.
6. Disconnect negative battery cable if working near oxygen sensor wiring to prevent fault codes.

Procedure

1. 1

   Disconnect upstream oxygen sensor
   Locate the upstream oxygen sensor on the inlet side of the catalytic converter. Disconnect the electrical connector by pressing the release tab and pulling straight out. Using an oxygen sensor socket or 22mm crow's foot wrench, carefully unthread the sensor counterclockwise. Apply light penetrating oil if sensor is difficult to remove. Remove sensor completely and set aside in a clean area.
2. 2

   Disconnect downstream oxygen sensor
   Locate the downstream oxygen sensor on the outlet side of the catalytic converter (before the DPF). Disconnect the electrical connector. Using an oxygen sensor socket or 22mm crow's foot wrench, carefully unthread the sensor counterclockwise. Remove sensor completely and set aside in a clean area away from contaminants.
3. 3

   Remove heat shield fasteners (if equipped)
   If the catalytic converter has a heat shield installed, remove the heat shield bolts using appropriate socket. Note the location and orientation of heat shield brackets for reinstallation. Remove heat shield and set aside.
   Torque spec

   Heat Shield Bolts10 Nm (7 lb-ft)
4. 4

   Support catalytic converter
   Position a transmission jack or suitable support under the catalytic converter assembly to support its weight during removal. The converter weighs approximately 30-40 pounds and must be supported before unbolting.
5. 5

   Remove inlet flange connection
   Locate the inlet flange connection between the turbocharger outlet pipe and catalytic converter inlet. Remove the flange bolts/nuts using appropriate socket. There are typically 3-4 bolts at this connection. If bolts are seized, apply additional penetrating oil and allow to soak. Once all fasteners are removed, carefully separate the flange connection. You may need to use a pry bar or exhaust separator tool to break the gasket seal.
   Torque spec

   Exhaust Flange Bolts45 Nm (33 lb-ft)
6. 6

   Remove outlet flange connection
   Locate the outlet flange connection between the catalytic converter outlet and DPF inlet. Remove the flange bolts/nuts using appropriate socket. Typically 3-4 bolts secure this connection. Carefully separate the flange connection once all fasteners are removed.
   Torque spec

   Exhaust Flange Bolts45 Nm (33 lb-ft)
7. 7

   Remove exhaust hanger supports
   Locate any rubber exhaust hangers or support brackets attached to the catalytic converter assembly. Remove the hanger bolts using appropriate socket. Gently work the hangers free from their mounting points. Note the position of all hangers for proper reinstallation.
   Torque spec

   Hanger Bolts27 Nm (20 lb-ft)
8. 8

   Remove catalytic converter assembly
   With all connections disconnected, carefully lower the catalytic converter assembly using the support jack. Maneuver the assembly out from under the vehicle. Inspect the unit for damage, excessive carbon buildup, or substrate failure to confirm replacement is necessary.
9. 9

   Clean mounting surfaces
   Using a wire brush and scraper, thoroughly clean all flange mounting surfaces on the turbocharger outlet pipe and DPF inlet pipe. Remove all old gasket material, carbon deposits, and corrosion. Clean the oxygen sensor bungs with a thread chaser or tap if available. Ensure mounting surfaces are flat and free of debris.
10. 10

    Prepare new catalytic converter
    Unpack the new catalytic converter and verify it matches the original unit in size, flange configuration, and oxygen sensor bung locations. Install new exhaust flange gaskets on both inlet and outlet flanges of the new converter. Ensure gaskets are properly seated.
11. 11

    Install new catalytic converter
    Using the support jack, carefully raise the new catalytic converter into position under the vehicle. Align the inlet flange with the turbocharger outlet pipe and outlet flange with the DPF inlet pipe. Reattach exhaust hangers to their mounting points first to help hold alignment. Install hanger bolts finger-tight initially.
12. 12

    Install and torque flange connections
    Install new flange bolts/nuts (or reuse if in good condition) at both inlet and outlet flanges. Apply anti-seize compound to bolt threads as specified. Start all bolts finger-tight. Torque inlet flange bolts (turbocharger side) to specification in a cross-pattern. Then torque outlet flange bolts (DPF side) to specification in a cross-pattern. Finally, torque hanger bolts to specification.
    Torque spec

    Exhaust Flange Bolts45 Nm (33 lb-ft)

    Hanger Bolts27 Nm (20 lb-ft)
13. 13

    Install oxygen sensors
    Apply a small amount of anti-seize compound to the threads only of both oxygen sensors. Do not allow anti-seize to contact the sensor tip. Thread each oxygen sensor into its respective bung by hand to avoid cross-threading. Torque upstream oxygen sensor to specification, then torque downstream oxygen sensor to specification using oxygen sensor socket or crow's foot wrench. Reconnect electrical connectors to both sensors ensuring they click fully into place.
    Torque spec

    O2 Sensor45 Nm (33 lb-ft)
14. 14

    Reinstall heat shield (if equipped)
    If heat shield was removed, position it back over the catalytic converter in its original orientation. Install heat shield bolts and torque to specification. Ensure heat shield is not contacting exhaust pipes or creating rattle points.
    Torque spec

    Heat Shield Bolts10 Nm (7 lb-ft)

Reassembly

1. Reconnect negative battery cable if it was disconnected.
2. Lower vehicle from jack stands carefully and remove support equipment.
3. Double-check that all exhaust connections are secure and no tools or parts have been left under the vehicle.

Verification

• Start engine and allow to idle. Listen for exhaust leaks at flange connections and oxygen sensor bungs. Any hissing or ticking sounds indicate a leak that must be corrected.
• With engine running, visually inspect all connections for exhaust gas escaping. Use caution as exhaust will be hot.
• Rev engine to approximately 2000 RPM and listen for any rattles or unusual noises from the exhaust system.
• Using a scan tool, verify that both oxygen sensors are reading properly and no diagnostic trouble codes are present. Clear any codes that were set during installation.
• Road test vehicle for 10-15 minutes to ensure proper operation and allow exhaust system to heat cycle. Recheck all connections for leaks after test drive.
• Perform final inspection under vehicle once cooled to verify all fasteners remain tight and no leaks are present.

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