Walker 54378 Exhaust Muffler Assembly - Rear

Walker Quiet-Flow SS Muffler Assembly

Walker Quiet-Flow SS 54378 is a direct-fit exhaust muffler assembly built for rear installation on select Nissan Pathfinder and INFINITI QX4 models. It uses stainless steel for the muffler body and internal construction, with an OE-style layout that supports a clean replacement for the original exhaust component.

The Quiet-Flow SS line focuses on stainless-steel construction for longer service life than typical aluminized mufflers, while maintaining a factory-style fit for domestic and foreign vehicles. This part number, 54378, is a practical choice for drivers looking for a replacement muffler assembly that matches the original routing and connection style.

Key Features

• Walker Quiet-Flow SS line for OE-style exhaust replacement
• Stainless steel muffler material and body material
• Round muffler shape with a 5-inch body diameter
• Center inlet and center outlet configuration
• 2-bolt welded flange inlet for secure connection
• Pipe connection outlet for direct-fit exhaust routing
• Overall length: 46.5 inches
• Cross-reference: Walker Exhaust 54377

Detailed Description

Walker 54378 is an exhaust muffler assembly engineered for rear placement on 2001-2004 Nissan Pathfinder and 2001-2003 INFINITI QX4 models. It features a combination muffler design with a 2.1-inch inlet outside diameter and a 2.25-inch outlet outside diameter, along with a round stainless-steel body measuring 12 inches long, 5 inches wide, and 5 inches high. The aluminized finish is paired with stainless-steel construction where it matters most for durability and exhaust service life.

For shoppers searching for a rear muffler assembly for 2001-2004 Nissan Pathfinder or a direct-fit muffler for 2001-2003 INFINITI QX4, part number 54378 provides an OE-style replacement that follows the original inlet and outlet layout. It is also listed as a cross-reference to Walker Exhaust 54377 for the same application.

Common Problems This Part Can Address

• Rust or corrosion in the original muffler assembly
• Exhaust noise caused by a damaged or failing muffler
• Fitment issues from a worn factory-style rear muffler
• Restricted exhaust flow from internal muffler deterioration
• Need for a direct-fit replacement on Nissan Pathfinder and INFINITI QX4 models

Installation Notes and Tips

Verify inlet and outlet diameters, flange style, and rear-position fitment before installation. This assembly uses a 2-bolt welded flange inlet and pipe connection outlet, so matching the existing exhaust connection points is important for proper alignment on the vehicle.

Confirm application details for your specific 2001-2004 Nissan Pathfinder or 2001-2003 INFINITI QX4 before ordering. Professional exhaust installation is recommended when replacing a rear muffler assembly to ensure correct sealing, alignment, and hanger positioning.

Quality Assurance

Walker Quiet-Flow SS muffler assemblies are built with stainless-steel construction and OE-style replacement fitment for long-term exhaust service. This part is backed by a limited lifetime warranty.