Cummins 4965340 / Q621548 / 5287478 DOC Replacement

OEM Cross Reference Interchange Matrix

Instant Fitment Verification: This direct-fit catalyst replaces components stamped with housing numbers, casting codes, or tag profiles matching any of the interchangeable manufacturing references listed below:

Restore commercial fleet emissions performance with this premium Skyline aftermarket Cummins & PACCAR 4965340 / Q621548 DOC Inlet Module Replacement Kit. This brand-new flow-through catalyst module functions as an absolute match for factory-stamped numbers 4965340 and Q621548, seamlessly cross-referencing factory service re-man component builds including 4965340-NX, 5287478-NX, and 5287478-RX. Engineered for an exact fit out of the box with zero exhaust system modifications required, it installs cleanly into the factory setup, carries zero core charge, and ships out in a plain white box with free standard ground shipping within the continental United States.

Choose Your Kit Configuration

Select the setup from the product options above that best fits your shop's needs:

• Full Kit (Best Value): Includes (1) Brand-New Component, (2) installation gaskets (2871451, 2866636), and (2) heavy-duty clamps (2871861, 2880482) linked cleanly via internal absolute paths.
• Component Only: Includes core unit only. Hardware items excluded.

Key Features & Specifications for Part 4965340 / Q621548

• Proudly Built in the USA: Designed, engineered, and manufactured in America.
• No Core Charge: Brand-new aftermarket component; completely eliminates dirty core tracking and return hassles.
• Exact-Fit™ Technical Dimensions: Built with matching inlet/outlet outer diameters, pre-machined sensor ports, and specialized body hanger brackets for zero exhaust system modifications.
• Substrate Performance Matrix: Advanced flow-through catalyst core uses verified washcoat metal loading to sustain exhaust temperature control and lower backpressure limits.
• Industry-Leading Warranty: Backed by an extensive 3-year unlimited mileage coverage matrix.
• EPA Compliant: Meets all federal emissions standards for legal installation nationwide.
• Fast Free Shipping: Free standard ground freight within the continental United States. Overnight and expedited shipping options are available at checkout. Orders confirmed before 2:00 PM Eastern ship out the same business day.

Vehicle Fitment Guide

Direct alternative solution for supported model year commercial configurations running horizontal chassis architectures:

• Engine Platforms: Highly optimized for Cummins ISB and PACCAR PX6 powertrain architectures approximate model years 2007-2009.
• Chassis Fitments: Extensively deployed across medium-duty regional transport setups, school buses, vocational trucks, delivery applications, and fleet chassis vehicles matching engine requirements.

Signs Your Diesel Oxidation Catalyst (DOC) Needs Replacement

• Frequent, unprompted, or incomplete DPF regeneration cycles linked directly to upstream catalyst efficiency degradation matching part numbers 4965340 / Q621548
• Excessive particulate soot face-plugging or heavy face mask scaling across the internal catalyst face assembly
• Active dashboard diagnostic trouble codes (DTCs) pointing directly to poor catalyst conversion efficiencies or thermal response delays
• Unexplained commercial engine backpressure spikes or noticeable horsepower deterioration under loaded transport pulls

*Note: Always verify exact vehicle compatibility using your vehicle's VIN number, emissions family descriptor tag, or the original stamped part number on your catalyst unit casing before placing an order.

Disclaimer: Product images for reference only. Hardware depends on configuration. Price is for (1) unit. Inventory levels are subject to local availability updates. Selecting the "Full Kit" option adds the explicitly listed installation components to your shipment.