National 320603 Manual Transmission Input Shaft Seal

Manual Transmission Input Shaft Seal for Toyota Applications

National 320603 is a metric manual transmission input shaft seal built with nitrile material and a clockwise-spiral lip design. It is sized for a 25.000 mm shaft and a 37.000 mm housing bore, making it a direct-fit sealing solution for a wide range of Toyota, Scion, Pontiac, Chevrolet, and Geo manual transmission applications.

Key Features

• Nitrile construction for dependable sealing performance in transmission service
• Clockwise-spiral lip design to support controlled oil sealing at the input shaft
• Metric dimensions: 25.000 mm shaft, 37.000 mm housing bore, 7.000 mm width
• Outside diameter of 37.260 mm and inside diameter of 25.000 mm
• National 320603 / Series 320000 oil seal design
• Fits many Toyota Corolla, Celica, Echo, MR2 Spyder, Yaris, and related manual transmission applications

Detailed Description

National 320603 is a manual transmission input shaft seal engineered for metric applications that require a 25 mm shaft diameter and a 37 mm housing bore. The nitrile sealing material is selected for transmission oil sealing, while the clockwise-spiral lip design helps maintain contact at the shaft interface. This part number is commonly used across Toyota C50, C59, C60, C56, C151, C150, C141, C140, C52, C51, and C65M transmission applications, including Toyota Corolla, Toyota Matrix, Toyota Celica, Toyota Echo, Toyota MR2 Spyder, Toyota Tercel, Toyota Yaris, Scion xA, Scion xB, Scion xD, Pontiac Vibe, Chevrolet Prizm, Chevrolet Nova, and Geo Prizm. This part cross-references SKF 9846A for the same application.

What It Helps Address

• Transmission oil seepage at the input shaft
• Fluid loss around the manual transmission case
• Contamination from worn or hardened seal material
• Noise or drivability concerns related to low transmission fluid level
• Service replacement during clutch or transmission maintenance

Installation Notes and Tips

Verify shaft diameter, housing bore, and transmission code before installation. Clean the bore and shaft surface thoroughly, and inspect for scoring or wear that could affect sealing. Confirm the application matches the vehicle and transmission combination, such as Fits 2003-2013 Toyota Corolla, with Toyota C59 Transmission; Fits 2000-2005 Toyota Celica, with Toyota C56 Transmission; and Fits 2006-2015 Toyota Yaris, with Toyota C50 Transmission. National 320603 is also listed for Fits 2008-2014 Scion xD, with Toyota C50 Transmission and Fits 2003-2010 Pontiac Vibe, with Toyota C59 Transmission.

Quality Assurance

National has supplied sealing solutions for more than 75 years and continues to develop OE-style sealing products for modern vehicles. The 320603 reflects that experience with a metric oil seal design intended for consistent transmission sealing performance.