Honda - Genuine Honda Oem B-Series Countershaft Bearing | 91003-P21-003

Genuine Honda OEM upper countershaft ball bearing for select Honda and Acura manual transmissions, including B-Series applications.

Located at the upper end of the transmission countershaft, this bearing is responsible for supporting and accurately locating the countershaft inside the transmission case while allowing it to rotate smoothly under load. The countershaft carries multiple transmission gears and is constantly subjected to rotational and radial forces during acceleration, deceleration and gear changes.

A properly functioning countershaft bearing helps maintain correct shaft alignment and smooth gear operation while minimizing unwanted countershaft movement and friction. A worn or damaged bearing can contribute to transmission whine, growling or rumbling noises, rough bearing operation and excessive countershaft play.

This is an important replacement component when rebuilding or refreshing a Honda B-Series manual transmission, particularly when replacing worn internal bearings or restoring a high-mileage gearbox.

Specifications:

• Genuine Honda OEM component
• Honda Part Number: 91003-P21-003
• Manufactured by NTN
• Type: Upper / Top Countershaft Ball Bearing
• Inside Diameter: 25 mm
• Outside Diameter: 52 mm
• Width: 14/15 mm
• Designed to support and locate the transmission countershaft
• Helps maintain proper countershaft and gear alignment
• Reduces rotational friction and unwanted shaft movement
• Made in Japan
• Quantity: 1 bearing

B-Series Applications:
Used in select Honda B-Series manual transmissions, including B16 applications such as the Civic Si and Del Sol VTEC, as well as compatible B18/B-Series gearboxes that specify Honda part number 91003-P21-003.

Perfect For:
B-Series transmission rebuilds, bearing replacement, gearbox restoration and preventative replacement while the transmission is disassembled.

Fitment Note:
Honda used 91003-P21-003 in multiple transmission families. Always verify your transmission application and OEM part number before ordering.

Vehicle Fitment

• 1992-2001 Acura Integra
• 1988-1991 Honda CRX
• 1988-2005 Honda Civic
• 1993-1997 Honda Del Sol
• 2007-2013 Honda Fit

LOCATION: BIN B-3