SKF 21390A Transfer Case Output Shaft Seal - Rear

Transfer Case Output Shaft Seal for Ford Super Duty

SKF 21390A is a transfer case output shaft seal built for rear applications on select Ford Super Duty trucks. It is designed with a 2.114 shaft diameter, 0.441 width, and HMSA92 seal type to help maintain a proper seal at the transfer case output shaft.

Compatible With 2017-2018 Ford F-250 Super Duty, rear, and 2017-2018 Ford F-350 Super Duty, rear, this SKF transfer case output shaft seal supports the sealing needs of flange type transfer case output setups. The SKF 21390A is a direct-fit style service part for these listed applications.

Key Features

• Transfer case output shaft seal for rear position applications
• 2.114 shaft diameter for the listed Ford Super Duty fitments
• 0.441 width for proper sealing dimensions
• HMSA92 seal type
• SKF-engineered seal design using premium materials
• Interchange reference: HC3Z7B215B

Detailed Description

SKF 21390A is a transfer case output shaft seal developed for 2017-2018 Ford F-250 Super Duty and 2017-2018 Ford F-350 Super Duty rear applications with a flange type transfer case output. SKF has a long history in shaft seal design, and this part reflects that focus with application-specific dimensions and sealing materials selected for the operating environment. Use SKF 21390A when servicing the transfer case output area on these Ford Super Duty trucks and when a precise rear output seal is required.

This part cross-references HC3Z7B215B for the same application.

Common Problems This Seal Can Address

• Transfer case fluid leakage at the rear output shaft
• Contamination entering the transfer case through a worn seal
• Wet or oily residue around the output shaft area
• Seal wear from age, heat, and driveline movement
• Service replacement for damaged or hardened sealing lips

Installation Notes and Tips

Confirm the vehicle uses a flange type transfer case output before ordering. Inspect the output shaft, flange surface, and surrounding sealing area for wear or damage before installing the new seal. Clean the housing thoroughly and verify the seal seats evenly to help maintain proper sealing performance.

Quality Assurance

SKF manufactures seals to specific designs with premium materials and quality-controlled production standards. The brand’s seal engineering heritage and application-focused manufacturing support long service life and dependable sealing performance in the listed Ford Super Duty applications.