Outer Differential Pinion Seal for 1994-2003 Dodge Ram 1500 & More - National 5778

Help keep gear oil inside the axle and road grit out of the gears with the National Differential Pinion Seal, part number 5778. It fits many vehicles, among them the 1975-1996 Ford F-150, 1994-2003 Dodge Ram 1500 and 1987-1995 Jeep Wrangler, and is a direct-fit replacement for the listed applications.

A pinion seal sits where the pinion shaft enters the differential housing. The seal body stays stationary while it seals against the rotating pinion yoke. It is designed to hold differential lubricant in and keep water, dust and dirt away from the gear set.

• Position: cataloged for the front outer and rear outer pinion positions, depending on the application.
• Quantity per application: the listed applications use one seal.
• Part number: National Oil Seal 5778.
• Coverage: fits a wide range of trucks, Jeeps and classic cars; the full list is on the Buyer's Guide tab.

Signs a pinion seal may need replacing include gear oil seeping or dripping around the pinion yoke, an oily film on the differential housing near the driveshaft connection, and a falling differential fluid level. A leak can also come from other seals or a loose cover, so find the source before you replace anything. Consult the vehicle service information for the installation procedure, pinion nut torque and any preload requirements.

See the Buyer's Guide tab for the full list of compatible vehicles.