Catalytic Converter for Dodge Ram 1500 (2004-2005) 3.7L 4.7L Left & Right

Direct-Fit Left & Right Catalytic Converter Set for 2004-2005 Dodge Ram 1500 (DR)

What it Does: The catalytic converter set replaces deteriorated factory emissions equipment on the 2004-2005 Dodge Ram 1500 to eliminate P0420/P0430 DTCs, restore exhaust gas velocity, and maintain Federal EPA compliance.

The Stock Dodge Ram 1500 Substrate Degradation

Factory catalytic converters on the third-generation DR chassis Dodge Ram 1500 are prone to washcoat degradation and substrate sintering over extended duty cycles. On both the PowerTech 3.7L V6 and PowerTech 4.7L V8, sustained operating temperatures and upstream blow-by or rich-condition misfires cause the ceramic honeycomb matrix to clog or break apart. This thermal breakdown creates restrictive exhaust backpressure, elevates EGTs, chokes engine breathing, and triggers recurring catalyst efficiency trouble codes.

The Engineering Solution

Constructed with durable stainless steel outer bodies, this direct-fit driver and passenger side catalytic converter pair features high-flow ceramic substrates loaded with washcoat formulations engineered to meet Federal EPA standards. The assemblies incorporate factory-profile 2-bolt loose inlet flanges with precision flares and OE-spec slip joints—utilizing a 2.25-inch OD outlet on the left pipe (645438) and a 2.50-inch OD outlet on the right pipe (645854). Integrated dual O2 sensor bungs per side provide factory sensor positioning to safeguard downstream closed-loop fuel feedback control without throwing false CELs.

What's Included

• 1 Left Catalytic Converter (Part # 645438)
• 1 Right Catalytic Converter (Part # 645854)
• Outlet Mounting Hardware

Technical Specifications

Compatibility

• 2004-2005 Dodge Ram 1500 3.7L V6
• 2004-2005 Dodge Ram 1500 4.7L V8 (Gas and Flex Fuel)

Frequently Asked Questions & Fitment Warnings

Does this fit the DR Ram 1500?

Yes, this is a direct fit for the 2004-2005 Dodge Ram 1500 equipped with the PowerTech 3.7L or 4.7L engine; it is not legal for sale or use in California, Colorado, New York, or Maine.

Should oxygen sensors be replaced during installation?

Yes, replacing upstream and downstream O2 sensors is strongly recommended alongside rectifying any underlying misfires or trim imbalances to avoid thermal shock to the new ceramic substrate.

The Dodge Ram Heavy-Duty Standard

Engineered to handle severe towing and daily payload duties, this stainless steel direct-fit exhaust hardware maintains critical backpressure balance and exhaust gas scavenging under sustained heavy load conditions.