Honda 07-15 Civic Si / 06-14 TSX K-Series Needle Bearing 35x41x24mm
Part Number: 91103-RAS-003

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Product Details

The Honda OEM K-Series Manual Transmission Mainshaft Needle Bearing is a genuine factory replacement designed to provide smooth gear rotation, precise shaft support, and dependable performance in compatible Honda and Acura 6-speed manual transmissions.

Manufactured to Honda's original equipment specifications, this precision-engineered needle roller bearing measures 35mm x 41mm x 24mm and is designed for the mainshaft assembly in select K-Series manual transmissions.

Commonly used in the 2007–2015 Honda Civic Si and select Acura TSX and ILX 6-speed manual transmissions, this genuine Honda bearing is an excellent replacement for worn or damaged original transmission components.

Needle roller bearings utilize cylindrical rollers to provide rotational support within a compact space. This design allows the mainshaft and associated transmission components to operate smoothly while maintaining proper alignment under changing drivetrain loads.

Over time, needle bearings can develop wear from high mileage, contaminated transmission fluid, excessive drivetrain loads, or aggressive driving. A worn mainshaft needle bearing may contribute to transmission whining, abnormal vibration, rough rotation, or accelerated wear of surrounding gearbox components.

Whether you're rebuilding a K20Z3 Civic Si transmission, refreshing a K24Z7 gearbox, or preparing a K-Series drivetrain for a performance build, this genuine Honda OEM Mainshaft Needle Bearing provides factory-correct dimensions and dependable construction.

Features

Genuine Honda OEM Part: Authentic factory replacement manufactured to Honda's original equipment specifications.
Mainshaft Needle Bearing: Designed to support the mainshaft in compatible K-Series manual transmissions.
Needle Roller Bearing Construction: Uses cylindrical rollers to provide smooth rotational support in a compact assembly.
35mm Inner Diameter: Factory-specified bearing inner diameter.
41mm Outer Diameter: Designed to match the corresponding factory transmission component.
24mm Width: Maintains the original bearing dimensions.
Direct OEM Replacement: Replaces the original bearing where Honda specifies part number 91103-RAS-003.
Factory-Correct Fit: Maintains the intended bearing geometry and mainshaft support.
Smooth Transmission Operation: Helps minimize friction and maintain proper rotating component alignment.
Ideal for Transmission Rebuilds: Excellent for K-Series 6-speed manual transmission maintenance and rebuilding.
Performance Build Friendly: Suitable for compatible naturally aspirated, turbocharged, and supercharged K-Series drivetrain projects.
Sold Individually: Includes one genuine Honda mainshaft needle bearing.
OEM Part Number: 91103-RAS-003.

Additional Information

Manufacturer: Honda / Acura
Part Number: 91103-RAS-003
OEM Description: Bearing, Needle (35x41x24)
Other Names: Mainshaft Needle Bearing / Mainshaft Roller Bearing / Manual Transmission Needle Bearing / K-Series Transmission Bearing
Product Type: Manual Transmission Bearing
Installation Location: Mainshaft Assembly
Bearing Type: Needle Roller Bearing
Inner Diameter: 35mm
Outer Diameter: 41mm
Width: 24mm
Quantity: Sold Individually (1 Bearing)

Common Reasons for Replacement

Manual transmission needle bearings should be inspected whenever the gearbox is disassembled for maintenance or rebuilding.

Abnormal transmission whining or grinding noises
Rough or noisy mainshaft rotation
Worn or damaged needle rollers
Pitting or deterioration of bearing surfaces
Excessive wear of the associated shaft or bearing surface
Contaminated or insufficient transmission fluid
High-mileage transmission rebuilding
Gear or synchronizer replacement
K20Z3 or K24Z7 transmission restoration
Performance transmission assembly
Replacing a worn mainshaft needle bearing helps restore proper shaft support and may prevent additional damage to surrounding transmission components.

Installation Notes

Proper installation is essential for maintaining correct transmission shaft alignment and bearing performance.
Before installation, inspect the mainshaft, bearing seating surfaces, transmission case, and surrounding components for wear or damage.
Confirm that the replacement bearing matches the original component's dimensions and specifications.
Clean the bearing installation area and remove any accumulated debris or contaminated lubricant.
Use the appropriate bearing installation tools and follow the Honda factory service procedure to ensure the bearing is properly seated.
Important: Avoid applying excessive or uneven force during installation. Improper installation can damage the bearing cage, needle rollers, or surrounding transmission components.
Inspect related transmission bearings, synchronizers, gears, and shaft components while the gearbox is disassembled.
Follow the Honda factory service manual for the correct installation procedures, transmission clearances, and reassembly specifications.
After reassembly, refill the transmission with the manufacturer-specified manual transmission fluid and verify proper operation.

Note:

Includes one genuine Honda OEM Mainshaft Needle Bearing (35x41x24mm). Transmission shafts, gears, synchronizers, seals, and additional bearings are sold separately unless otherwise specified.

For Honda and Acura enthusiasts rebuilding a Civic Si or TSX manual transmission, restoring a factory K-Series drivetrain, or preparing a performance gearbox, this genuine Honda OEM Mainshaft Needle Bearing delivers factory-correct dimensions, precise shaft support, and dependable transmission performance.

Part Number:	91103-RAS-003
Brand:	Honda

WARNING: This product may contain chemicals known to the State of California to cause cancer or birth defects. www.P65Warnings.ca.gov.

Vehicle Fitment

Year	Make	Model	Trim
2006	Acura	TSX	Base
2007	Acura	TSX	Base
2007	Honda	Civic	Si
2008	Acura	TSX	Base
2008	Honda	Civic	MUGEN Si
2008	Honda	Civic	Si
2009	Acura	TSX	Base
2009	Honda	Civic	Si
2010	Acura	TSX	Base
2010	Honda	Civic	Si
2011	Acura	TSX	Base
2011	Honda	Civic	Si
2012	Acura	TSX	Base
2012	Acura	TSX	Special Edition
2012	Honda	Civic	Si
2013	Acura	ILX	Base
2013	Acura	TSX	Base
2013	Acura	TSX	Special Edition
2013	Honda	Civic	Si
2014	Acura	ILX	Base
2014	Acura	TSX	Base
2014	Acura	TSX	Special Edition
2014	Honda	Civic	Si
2015	Acura	ILX	Base
2015	Honda	Civic	Si