Walker 21736 Exhaust Muffler - Rear

Walker Quiet-Flow Muffler for Audi A4

Walker Quiet-Flow 21736 is a specific-fit exhaust muffler built for rear installation on select Audi applications. It combines a 2.5-inch inlet and dual 2.5-inch outlets with an OE-style sound profile and a flow-focused internal design.

Use this muffler when you need a direct replacement for the factory exhaust layout on 2009-2013 Audi A4, 2009-2012 Audi A4 Quattro, and 2010-2011 Audi A5 Quattro rear applications.

Key Features

• Part number 21736
• Walker Quiet-Flow product line
• Specific fit for rear exhaust placement
• 2.5-inch inlet outside diameter
• Dual 2.5-inch outlet outside diameters
• Combination muffler type with dual tips
• Steel body with aluminized finish
• Offset inlet configuration
• Irregular body shape
• Limited lifetime warranty and 90-day Safe and Sound guarantee

Product Details

Walker Quiet-Flow mufflers are built for drivers who want a replacement muffler that follows OE-style sound characteristics while maintaining exhaust flow. This unit uses a single pipe-connection inlet and dual pipe-connection outlets, making it a direct match for the listed rear exhaust applications. The aluminized finish and steel construction support everyday corrosion resistance in a standard replacement setup. If you are sourcing a Walker 21736 muffler for an Audi A4 or Audi A4 Quattro, this part is configured for the factory-style rear exhaust arrangement.

This part cross-references Audi OE number 8K0253609 for the same application.

What It Helps Address

• Damaged or rusted rear muffler assembly
• Exhaust noise that is louder than factory levels
• Restricted exhaust flow from a worn muffler
• Need for a direct-fit replacement on Audi A4 and Audi A5 Quattro rear applications
• Factory exhaust outlet configuration replacement

Installation Notes

Confirm the vehicle year, model, and rear exhaust layout before installation. This muffler is not reversible and is not tunable, so orientation matters during fitment. Verify the 2.5-inch inlet and dual 2.5-inch outlet dimensions against the existing exhaust system before final assembly.

Quality Assurance

Walker backs Quiet-Flow mufflers with a limited lifetime warranty and a 90-day Safe and Sound guarantee. The Quiet-Flow line is positioned as an OE-style replacement option for top-selling domestic and foreign vehicles, including select Audi A4, Audi A4 Quattro, and Audi A5 Quattro applications.