InMotion WS4638N Manual Transmission Input Shaft Seal

Manual Transmission Input Shaft Seal for NP4500

The InMotion WS4638N is a manual transmission input shaft seal built with polyacrylate material for a precise sealing fit. It is specified for New Process 4500 and 4500HD transmission applications across a wide range of Chevrolet, GMC, and Dodge trucks.

Key Features

• Polyacrylate construction for durable sealing performance
• Inside diameter: 1.375 in.
• Outside diameter: 1.989 in.
• Thickness: 0.192 in.
• Shaft diameter: 1.375 in.
• Housing bore: 1.982 in.
• Fits New Process 4500 and New Process 4500HD manual transmissions
• Part number WS4638N for easy identification

Detailed Description

InMotion WS4638N is a manual transmission input shaft seal engineered to maintain a secure barrier at the transmission opening. Its polyacrylate sealing material is selected for dimensional stability and resistance to contamination intrusion, helping keep moisture and debris away from sensitive internal transmission components. With precise measurements for the shaft and housing bore, this seal is suited for service work on NP4500 and NP4500HD-equipped trucks, including Chevrolet Silverado 1500, Silverado 2500 HD, Silverado 3500, GMC Sierra 1500, Sierra 2500 HD, Sierra 3500, and Dodge Ram 2500 and Ram 3500 applications. The WS4638N is a direct-fit service part for technicians and owners replacing a worn or leaking input shaft seal.

Vehicle Fitment

• Fits 2007 Chevrolet Silverado 2500 HD Classic, with New Process 4500 Transmission
• Fits 2007 Chevrolet Silverado 3500 Classic, with New Process 4500HD Transmission
• Fits 2007 GMC Sierra 2500 HD Classic, with New Process 4500HD Transmission
• Fits 2007 GMC Sierra 3500 Classic, with New Process 4500 Transmission
• Fits 2002-2006 Chevrolet Silverado 1500, with New Process 4500 Transmission
• Fits 2006 Chevrolet Silverado 2500 HD, with New Process 4500HD Transmission
• Fits 2003-2004 Chevrolet Silverado 2500 HD, with New Process 4500HD Transmission
• Fits 2001 Chevrolet Silverado 2500 HD, with New Process 4500HD Transmission
• Fits 2005-2006 Chevrolet Silverado 3500, with New Process 4500HD Transmission
• Fits 2001 Chevrolet Silverado 3500, with New Process 4500HD Transmission
• Fits 2002-2006 GMC Sierra 1500, with New Process 4500 Transmission
• Fits 2002-2006 GMC Sierra 2500 HD, with New Process 4500 Transmission
• Fits 2006 GMC Sierra 3500, with New Process 4500 Transmission
• Fits 2001 GMC Sierra 3500, with New Process 4500 Transmission
• Fits 2005 Chevrolet Silverado 2500 HD, with New Process 4500 Transmission
• Fits 2002 Chevrolet Silverado 2500 HD, with New Process 4500 Transmission
• Fits 1994-2005 Dodge Ram 2500, with New Process 4500HD Transmission
• Fits 1994-2005 Dodge Ram 3500, with New Process 4500HD Transmission
• Fits 2002-2005 GMC Sierra 3500, with New Process 4500HD Transmission
• Fits 1999-2004 Chevrolet Silverado 2500, with New Process 4500 Transmission
• Fits 2002-2004 Chevrolet Silverado 3500, with New Process 4500 Transmission
• Fits 1999-2004 GMC Sierra 2500, with New Process 4500 Transmission
• Fits 2001 GMC Sierra 2500 HD, with New Process 4500HD Transmission
• Fits 1996-2000 Chevrolet C2500, with New Process 4500 Transmission
• Fits 1999-2000 Chevrolet C3500, with New Process 4500 Transmission
• Fits 1996-1997 Chevrolet C3500, with New Process 4500 Transmission
• Fits 1996-2000 Chevrolet K2500, with New Process 4500 Transmission
• Fits 2000 Chevrolet K3500, with New Process 4500 Transmission
• Fits 1996-2000 GMC C2500, with New Process 4500 Transmission
• Fits 2000 GMC C3500, with New Process 4500 Transmission
• Fits 1997-1998 GMC C3500, with New Process 4500 Transmission
• Fits 1996-2000 GMC K2500, with New Process 4500 Transmission
• Fits 2000 GMC K3500, with New Process 4500 Transmission
• Fits 1998 GMC K3500, with New Process 4500 Transmission
• Fits 1996-1999 Chevrolet K3500, with New Process 4500HD Transmission
• Fits 1999 GMC C3500, with New Process 4500HD Transmission
• Fits 1996 GMC C3500, with New Process 4500HD Transmission
• Fits 1999 GMC K3500, with New Process 4500HD Transmission
• Fits 1996-1997 GMC K3500, with New Process 4500HD Transmission
• Fits 1996-1999 GMC P3500, with New Process 4500 Transmission
• Fits 1996-1998 Chevrolet C1500, with New Process 4500 Transmission
• Fits 1998 Chevrolet C3500, with New Process 4500HD Transmission
• Fits 1996-1998 Chevrolet K1500, with New Process 4500 Transmission
• Fits 1996-1998 GMC C1500, with New Process 4500 Transmission
• Fits 1996-1998 GMC K1500, with New Process 4500 Transmission

Common Service Uses

• Replacing a leaking manual transmission input shaft seal
• Reducing fluid seepage at the transmission front opening
• Keeping dirt, road moisture, and debris out of the transmission
• Restoring sealing integrity on NP4500 and NP4500HD units
• Supporting maintenance on Chevrolet Silverado, GMC Sierra, and Dodge Ram manual transmission trucks

Installation Notes and Tips

Confirm the transmission model before installation; this seal is listed for New Process 4500 and 4500HD applications only. Inspect the input shaft, seal bore, and surrounding surfaces for wear, scoring, or contamination before installing WS4638N. Clean the housing thoroughly and verify the seal seats evenly to maintain proper sealing contact. For fitment searches, this part is commonly referenced for Chevrolet Silverado and GMC Sierra manual transmission service, as well as Dodge Ram 2500 and Ram 3500 NP4500 applications.

Quality Assurance

InMotion manufactures this seal with precision-focused dimensions and polyacrylate material selection to support consistent sealing performance in manual transmission service. Part number WS4638N is identified for accurate ordering and application matching.