Product Description
Shimano 10FNT Idle Gear (BNT4469)
The Shimano 10FNT Idle Gear (BNT4469) is a critical internal component of the levelwind system in high-torque baitcasting reels, most notably the Shimano Tranx series. This gear serves as the mechanical bridge between the main drive train and the worm shaft, ensuring that the levelwind tracks back and forth in perfect synchronization with the spool.
In a heavy-duty reel like the Tranx, which is designed for large lures and powerful game fish (Musky, Pike, Striped Bass, and Tuna), the idle gear is subjected to significant stress. While it is made of a high-impact polymer to reduce noise and allow for a "sacrificial" point of failure (to protect the more expensive metal main gears), it can wear out over time or strip if the levelwind becomes jammed with debris.
Product Specifications
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Part Name: Idle Gear
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Part Number: 10FNT
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Shimano Code: BNT4469
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Material: High-Strength Engineering Polymer
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Function: Drives the worm shaft (levelwind) from the drive shaft assembly.
Alternate Part Numbers
This part is a standard component for Shimano's high-capacity low-profile reels and is identified as:
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BNT4469
Compatibility & Fitment
The 10FNT (BNT4469) is a direct factory fit for the following heavy-duty Shimano series:
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Shimano Tranx Series: * TRX-300, TRX-301 (including HG and AHG models)
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TRX-400, TRX-401 (including HG and AHG models)
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TRX-500HG, TRX-500PG
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Shimano Curado Series:
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CU-300K, CU-301K
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CU-300DSV, CU-301DSV (Legacy models)
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Shimano Grappler: Select 300-size baitcasting models.
Key Features
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Synchronization: Precisely timed to match the spool's rotation, preventing line "dig-in" during heavy drags.
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Vibration Dampening: The polymer construction absorbs the micro-vibrations of the levelwind system, contributing to the "smooth" feel of the Tranx.
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Corrosion Immunity: Being non-metallic, it is entirely immune to salt crystallization that can seize or grind down metal gear teeth.
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Safety Link: Designed to be the "weakest link" in the levelwind system; if the guide gets jammed, this gear will strip its teeth to prevent the metal drive shaft or worm shaft from bending.
Maintenance & Troubleshooting
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Symptom of Failure: If your Tranx handle turns but the line guide doesn't move, or if you feel a "crunchy" sensation specifically when the line guide moves, the BNT4469 is likely stripped.
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Inspection: Check the teeth for "rounding" or missing sections. Even one missing tooth will cause the levelwind to stall or stack line unevenly.
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Lubrication: Use a light coating of Shimano Ace-2 (DG04) or DG06 grease. Do not over-grease, as excess grease can attract sand and grit, which acts like sandpaper on polymer gears.
Pro Tip: If you frequently fish in saltwater or dirty freshwater, check the Worm Shaft (BNT4471) for debris. A dirty worm shaft puts immense back-pressure on this idle gear, leading to premature failure. You can find the full internal layout for the Tranx at www.reelschematic.com.
