FAG 6308 Manual Transmission Main Shaft Pilot Bearing - Front or Rear

FAG 6308 Manual Transmission Bearing

The FAG 6308 is a manual transmission main shaft pilot bearing built for drivetrain service where precise shaft support and smooth rotation matter. With a 40.005 mm outside diameter, 1.575 in inside diameter, and 23.495 mm length, this bearing matches common OE-style dimensions for select Ford F-250, Ford F-350, and Nissan 720/D21 applications.

• Part number: 6308
• Bearing inside diameter: 1.575 in / 40.005 mm
• Bearing outside diameter: 3.543 in / 89.992 mm
• Length: 0.925 in / 23.495 mm
• Manual transmission main shaft pilot bearing application
• Cross-reference: AMS Automotive 6308

Fitment and application details

Compatible With 1996-1999 Ford F-250, rear; 1999 Ford F-250 Super Duty, rear; 1996-1997 Ford F-350, rear; 1980-1986 Nissan 720, front and rear; and 1986 Nissan D21, rear. Notes include Warner 4407 transfer case coverage on select Ford applications and dual rear wheel/hardbody notes on the Nissan D21. The FAG 6308 part number is also referenced in interchange listings for related service applications.

FAG develops and produces roller bearings, spherical bearings, and plain bearings for a wide range of industrial and automotive uses. That manufacturing background supports consistent bearing geometry and application-specific sizing for transmission service, including the FAG 6308.

Common issues this bearing can address

• Excessive shaft play in the manual transmission assembly
• Noise from a worn or rough pilot bearing
• Vibration caused by bearing wear or incorrect fitment
• Difficulty maintaining smooth drivetrain rotation under load
• Service replacement for worn transmission support components

Installation notes and tips

Verify the bearing dimensions against the transmission and transfer case application before installation. Inspect the shaft, bore, and surrounding components for wear, scoring, or contamination, and replace any damaged mating parts as needed. Proper seating and alignment are important for reliable operation in Ford F-250, Ford F-350, and Nissan 720/D21 service applications.

Quality assurance

FAG is a bearing manufacturer with global production experience across automotive and industrial categories. The 6308 bearing is built to dimensional specifications commonly used in drivetrain service, supporting accurate replacement selection for the listed applications.