SKF 18521 Manual Transmission Seal - Rear

SKF Manual Transmission Seal for Rear Applications

SKF Part Number 18521 is a manual transmission seal built for rear-position applications on a wide range of Chevrolet and GMC trucks and SUVs. It uses a polyacrylate sealing surface and precise dimensions to help maintain a tight seal at the shaft interface.

Fits 1988-2007 Chevrolet Silverado 1500, rear; Fits 1988-2007 GMC Sierra 1500, rear; and other listed rear manual transmission applications. This SKF 18521 seal is designed for vehicles that need dependable fluid retention and contamination control at the transmission shaft.

Key Features

• Manual transmission seal for rear installation points
• Polyacrylate sealing surface type for consistent sealing performance
• 1.890 shaft diameter for the specified application
• 2.568 outside diameter and 0.965 width for proper fitment
• Engineered by SKF, a long-established seal manufacturer
• Cross-reference: this part cross-references 23049496 for the same application

Detailed Description

SKF 18521 is a rear manual transmission seal made to match the dimensional and material requirements of the listed applications. SKF has a long history in seal design, and this part reflects that focus with premium material selection and application-specific construction. The polyacrylate sealing surface is selected to help maintain contact at the shaft while resisting the operating conditions found in transmission service.

Vehicle coverage includes Chevrolet Silverado 1500, Chevrolet Silverado 1500 Classic, Chevrolet Silverado 1500 HD, GMC Sierra 1500, GMC Sierra 1500 Classic, GMC Sierra 1500 HD, Chevrolet C1500, Chevrolet C2500, Chevrolet C35, Chevrolet Tahoe, GMC C1500, GMC C2500, and GMC Yukon in rear-position applications. If you are servicing a Chevrolet Silverado 1500 rear manual transmission seal or a GMC Sierra 1500 rear seal, SKF Part Number 18521 is built to match the listed fitment and dimensions.

What This Seal Helps Address

• Transmission fluid seepage at the rear shaft area
• Contaminant entry into the transmission housing
• Wear-related sealing loss at the shaft interface
• Leak concerns during manual transmission service
• Fitment issues when replacing a worn rear seal on listed Chevrolet and GMC models

Installation Notes and Tips

Confirm shaft diameter, outside diameter, and width before installation. Inspect the shaft surface and sealing bore for scoring, corrosion, or debris, and clean all mating surfaces before fitting the seal. Use proper installation tools to seat the seal evenly and avoid damaging the sealing lip or housing.

Verify the vehicle’s transmission configuration and rear-position application against the fitment list before ordering. For 1988 Chevrolet C2500, Chevrolet R20, GMC C2500, and GMC R2500 applications, note the Getrag transmission reference in the fitment data.

Quality Assurance

SKF designs and manufactures seals to specific application requirements using premium materials and controlled production standards. Part Number 18521 is built for long service life in the listed rear manual transmission applications and reflects SKF’s established seal engineering background.