Walker 55557 Catalytic Converter - Left

Walker EPA 55557 Catalytic Converter

Walker EPA 55557 is a direct-fit catalytic converter for select 2003-2007 Chevrolet Silverado and GMC Sierra trucks with Federal Emission systems. It uses a stainless steel body, a ceramic substrate, and OE-style inlet and outlet connections for a precise replacement on the left side.

Key Features

• Direct-fit design for specific applications
• Stainless steel body with small oval housing
• Ceramic substrate material
• 1 inlet and 1 outlet
• 3-bolt welded flange inlet and 3-inch pipe connection outlet
• Pre- and post-catalyst oxygen sensor locations
• EPA-compliant product line for OBDII vehicles
• Part number: 55557

Product Details

Walker EPA 55557 is part of the Walker Ultra Direct-Fit Catalytic Converter line, built for import and domestic OBDII vehicles from 1996 and newer. This converter is engineered for specific truck applications and follows EPA standards, making it a practical replacement for emissions-system service on a Chevrolet Silverado 2500 HD, Silverado 3500, Silverado 3500 Classic, GMC Sierra 2500 HD, Sierra 3500, and Sierra 3500 Classic. The unit measures 50 inches overall, with a 10-inch body length, 6-inch body width, and 4.25-inch body height.

This part cross-references Eastern Catalytic 50423 for the same application.

Vehicle Fitment

• Fits 2007 Chevrolet Silverado 3500 Classic, left, with Federal Emission System; not legal for sale or use in California and other CARB-compliant states. Legal in New York and Maine on EPA Federal Emission Equipped Vehicles only. Exhaust gasket is recommended.
• Fits 2007 GMC Sierra 3500 Classic, left, with Federal Emission System; not legal for sale or use in California and other CARB-compliant states. Legal in New York and Maine on EPA Federal Emission Equipped Vehicles only. Exhaust gasket is recommended.
• Fits 2003-2006 Chevrolet Silverado 2500 HD, left, with Federal Emission System; except Low Emission Vehicle (LEV). Not legal for sale or use in California and other CARB-compliant states. Legal in New York and Maine on EPA Federal Emission Equipped Vehicles only. Exhaust gasket is recommended.
• Fits 2003-2006 Chevrolet Silverado 3500, left, with Federal Emission System; not legal for sale or use in California and other CARB-compliant states. Legal in New York and Maine on EPA Federal Emission Equipped Vehicles only. Exhaust gasket is recommended.
• Fits 2003-2006 GMC Sierra 2500 HD, left, with Federal Emission System; except Low Emission Vehicle (LEV). Not legal for sale or use in California and other CARB-compliant states. Legal in New York and Maine on EPA Federal Emission Equipped Vehicles only. Exhaust gasket is recommended.
• Fits 2003-2006 GMC Sierra 3500, left, with Federal Emission System; not legal for sale or use in California and other CARB-compliant states. Legal in New York and Maine on EPA Federal Emission Equipped Vehicles only. Exhaust gasket is recommended.
• Fits 2004 Chevrolet Silverado 2500, left, with Federal Emission System; except Low Emission Vehicle (LEV). Not legal for sale or use in California and other CARB-compliant states. Legal in New York and Maine on EPA Federal Emission Equipped Vehicles only. Exhaust gasket is recommended.
• Fits 2004 GMC Sierra 2500, left, with Federal Emission System; except Low Emission Vehicle (LEV). Not legal for sale or use in California and other CARB-compliant states. Legal in New York and Maine on EPA Federal Emission Equipped Vehicles only. Exhaust gasket is recommended.

Installation Notes

Confirm Federal Emission system coverage before ordering, since this converter is not CARB certified. The 3-bolt welded flange inlet and pipe-style outlet are designed for direct replacement, and an exhaust gasket is recommended during installation. Verify oxygen sensor placement at both pre- and post-catalyst locations before final assembly.

Quality Assurance

Walker EPA 55557 is built to meet EPA standards for the listed applications and is part of Walker’s Ultra Direct-Fit line for OBDII vehicles. The stainless steel construction and application-specific fitment support consistent replacement quality for the covered Chevrolet Silverado and GMC Sierra models.