National 3604 Differential Pinion Seal - Front Outer, Rear or Rear Outer

National 3604 Differential Pinion Seal

National 3604 is a differential pinion seal built for driveline sealing applications where accurate dimensions and durable lip design matter. It uses a fluoro-elastomer material with a clockwise-spiral lip design and Redicoat coating to support consistent sealing performance in Ford, Lincoln, Mercury, Mazda, and Jaguar applications.

This seal is sized with a 1.812 inch inside diameter, 2.783 inch outside diameter, and 0.455 inch thickness. It also features a 3.150 inch flanged outside diameter and 0.591 inch overall width with side lip, making it a precise replacement for many Ford axle and differential setups.

Key Features

• Part number 3604 differential pinion seal from National
• Fluoro-elastomer construction for sealing durability
• Clockwise-spiral lip design
• Redicoat surface treatment
• 1.812 in. shaft / inside diameter and 2.783 in. outside diameter
• 0.455 in. width with 3.150 in. flanged outside diameter
• Compatible with many 8.8-inch and 7.5-inch Ford axle applications

Detailed Description

National has supplied sealing solutions for more than 75 years, and the 3604 reflects that focus on dimensional accuracy and modern sealing materials. This differential pinion seal is used in rear outer and front outer applications across a wide range of vehicles, including Ford F-150, Ford Expedition, and Lincoln Navigator models, as well as select Mustang, Explorer, Ranger, and Mazda B-series fitments. It is also listed for several Jaguar rear applications.

This part cross-references Bosch 18136 and 18190 for the same application. For buyers searching for a Ford F-150 rear outer differential pinion seal, a Ford Expedition front outer seal, or a Lincoln Navigator rear outer seal, National 3604 is a direct-fit option within the listed configurations.

Common Problems This Seal Can Address

• Gear oil leakage at the differential pinion area
• Contamination around the pinion shaft and housing bore
• Seal wear from age, heat, and driveline movement
• Noise or driveline mess caused by low lubricant level
• Replacement needs during axle or differential service

Installation Notes and Tips

Verify shaft diameter, housing bore, and axle configuration before installation. This seal is listed for multiple Ford axle variants, including 8.8-inch and 7.5-inch ring gear applications, so matching the exact vehicle, position, and axle type is important. Clean the bore and shaft surface thoroughly, and inspect the pinion area for wear before pressing in the new seal.

Use the fitment notes to confirm whether your vehicle requires a rear outer, front outer, or rear position. National 3604 is commonly searched as a differential pinion seal for Ford F-150, Ford Explorer, and Lincoln Navigator driveline repairs.

Quality Assurance

National is known for premium sealing solutions and long-standing industry experience. The 3604 uses a fluoro-elastomer sealing material, spiral lip geometry, and Redicoat treatment to support reliable sealing performance in demanding driveline environments.

• Fits 2001-2018 Ford Expedition, front outer, for models with 8.8 inch ring gear and Visteon axle, featuring independent front suspension.
• Fits 2001-2018 Ford F-150, rear outer, for models with 8.8 inch ring gear and Visteon axle.
• Fits 2001-2018 Ford F-150, front outer, for models with 8.8 inch ring gear and Visteon axle, featuring independent front suspension.
• Fits 2001-2018 Lincoln Navigator, front outer, for models with 8.8 inch ring gear and Visteon axle, featuring independent front suspension.
• Fits 2003-2014 Ford E-150, rear outer, for models with 8.8 inch ring gear and Visteon axle.
• Fits 2005-2014 Ford Mustang, rear outer, for models with 8.8 inch ring gear and Visteon axle.
• Fits 2001-2011 Ford Crown Victoria, rear outer, for models with 8.8 inch ring gear and Visteon axle.
• Fits 2001-2011 Ford Ranger, rear outer, for models with 8.8 inch ring gear and Visteon axle.
• Fits 2001-2011 Lincoln Town Car, rear outer, for models with 8.8 inch ring gear and Visteon axle.
• Fits 2001-2011 Mercury Grand Marquis, rear outer, for models with 8.8 inch ring gear and Visteon axle.
• Fits 2001-2010 Ford Explorer, rear outer, 8.8 inch ring gear, Visteon axle, independent rear suspension.
• Fits 2007-2010 Ford Explorer Sport Trac, rear outer, 8.8 inch ring gear, Visteon axle, independent rear suspension.
• Fits 2005-2009 Jaguar Super V8, rear.
• Fits 2004-2009 Jaguar Vanden Plas, rear.
• Fits 2009 Jaguar XF, rear.
• Fits 2004-2009 Jaguar XJ8, rear.
• Fits 2004-2009 Jaguar XJR, rear.
• Fits 2007-2009 Jaguar XK, rear.
• Fits 2007-2009 Jaguar XKR, rear.
• Fits 2000-2008 Jaguar S-Type, rear.