Restore smooth alternator operation with this 100% new aftermarket Denso 6-groove decoupler pulley, designed for compatible Denso IR/IF alternators. This replacement pulley helps reduce accessory belt vibration, minimize belt drive noise, and support reliable alternator performance.
Designed for select Cadillac CTS, Escalade, Chevrolet Camaro, Silverado, Suburban, Tahoe, Express, GMC Sierra, Yukon, and Savana applications. Ideal for alternator rebuilding and repair, this pulley is compatible with Lester number 14009 and cross-referenced to Denso 021040-2420 and GM 12645462.
Product Specifications
Product Type: Alternator Decoupler Pulley
Manufacturer: Aftermarket Replacement for Denso
Alternator Manufacturer: Denso
Alternator Series: Denso IR/IF
Pulley Type: Decoupler
Number of Grooves: 6
Condition: 100% New
Application: Alternator Rebuilding and Repair
Compatible Lester Numbers
14009
OEM Cross Reference
Denso:
021040-2420
General Motors (GM):
12645462
Alternator Unit Numbers
Denso:
104210-6870
General Motors (GM):
22949467
Vehicle Application
| Make | Model | Year | Engine |
|---|---|---|---|
| Cadillac | CTS | 2016–2018 | V8 6.2L 6162cc 376cid |
| Cadillac | Escalade ESV | 2015–2018 | V8 6.2L 6162cc 376cid |
| Cadillac | Escalade | 2015–2019 | V8 6.2L 6162cc 376cid |
| Chevrolet | Camaro | 2016–2018 | V8 6.2L 6162cc 376cid |
| Chevrolet | Express 2500 | 2017–2022 | L4 2.8L 171cid DIESEL; VIN 1; LWN; Turbocharged |
| Chevrolet | Express 3500 | 2017–2022 | L4 2.8L 171cid DIESEL; VIN 1; LWN; Turbocharged |
| Chevrolet | Silverado 1500 | 2014–2018 | V6 4.3L 262cid |
| Chevrolet | Silverado 1500 | 2014–2018 | V8 5.3L 5328cc 325cid VIN C |
| Chevrolet | Silverado 1500 | 2014–2018 | V8 6.2L 6162cc 376cid |
| Chevrolet | Suburban | 2015–2018 | V8 5.3L 5328cc 325cid VIN C |
| Chevrolet | Tahoe | 2015–2019 | V8 5.3L 5328cc 325cid VIN C |
| GMC | Savana 2500 | 2017–2022 | L4 2.8L 171cid DIESEL; VIN 1; LWN; Turbocharged |
| GMC | Savana 3500 | 2017–2022 | L4 2.8L 171cid DIESEL; VIN 1; LWN; Turbocharged |
| GMC | Sierra 1500 | 2014–2018 | V6 4.3L 262cid |
| GMC | Sierra 1500 | 2014–2018 | V8 5.3L 5328cc 325cid VIN C |
| GMC | Sierra 1500 | 2014–2018 | V8 6.2L 6162cc 376cid |
| GMC | Yukon XL | 2015–2018 | V8 5.3L 5328cc 325cid VIN C |
| GMC | Yukon XL | 2015–2018 | V8 6.2L 6162cc 376cid |
| GMC | Yukon | 2015–2019 | V8 5.3L 5328cc 325cid VIN C |
| GMC | Yukon | 2015–2019 | V8 6.2L 6162cc 376cid |
Fitment Note: Verify the original alternator number, Lester number 14009, Denso IR/IF alternator series, 6-groove decoupler design, OEM cross-reference numbers, and product photos before ordering. Vehicle compatibility may vary depending on engine configuration, alternator equipment, and production year.
Features & Benefits
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Precision aftermarket replacement clutch / decoupler pulley for compatible alternators
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Helps maintain smooth and efficient alternator drive operation
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Designed to reduce excessive accessory belt vibration and unwanted noise
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Helps minimize sudden belt loading during engine speed changes
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Supports proper operation of the alternator and accessory belt drive system
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Designed to replace worn, damaged, or malfunctioning alternator pulleys
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Manufactured for dependable fit, performance, and long service life
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Ideal for professional rebuilders, automotive repair shops, and DIY technicians
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Suitable for alternator rebuilding, maintenance, and repair
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Cross-referenced to OEM and aftermarket alternator part numbers for easier identification
What Does an Alternator Clutch / Decoupler Pulley Do?
An alternator clutch / decoupler pulley is a mechanical drive component that transfers rotational power from the engine's accessory belt to the alternator while helping manage changes in rotational speed and belt tension.
Unlike a conventional solid alternator pulley, an overrunning clutch pulley (OAP) incorporates a one-way clutch mechanism that allows the alternator rotor to continue rotating when engine speed decreases. This helps reduce sudden belt loading, vibration, and unnecessary stress on the accessory drive system.
An overrunning decoupler pulley (OAD) provides a similar overrunning function while incorporating a torsional spring mechanism that helps absorb engine speed fluctuations and reduce belt vibration.
A worn, seized, or malfunctioning clutch / decoupler pulley can contribute to excessive belt movement, abnormal tensioner operation, unwanted noise, or premature wear of related accessory drive components. Replacing a faulty pulley during alternator servicing can help restore proper pulley operation and support reliable accessory belt performance.
Clutch and decoupler pulley designs vary by alternator manufacturer and series. Always verify the pulley type, specifications, and compatibility before ordering.
Common Signs an Alternator Clutch / Decoupler Pulley May Need Replacement
Consider inspecting or replacing the clutch / decoupler pulley if you notice:
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Excessive serpentine belt vibration or flutter
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Unusual rattling, chirping, or squealing noises near the alternator
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Excessive belt tensioner movement during engine operation
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Pulley seized or locked in both directions when tested according to its design
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Pulley slipping or failing to engage properly
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Grinding, rattling, or abnormal mechanical noise from the pulley
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Excessive pulley wobble or noticeable mechanical play
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Premature serpentine belt or tensioner wear
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Visible cracks, damage, or deterioration of the pulley assembly
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Irregular accessory belt operation during acceleration or deceleration
Note: These symptoms may also be caused by worn belts, tensioners, bearings, or other accessory drive components. Proper diagnosis is recommended before replacement.
Installation Recommendations
Installation should be performed by a qualified technician or experienced alternator rebuilder. Before replacing the clutch / decoupler pulley, disconnect the battery and inspect the alternator shaft, accessory belt, belt tensioner, mounting hardware, and surrounding drive components for damage or deterioration.
Inspect the original pulley for excessive wear, mechanical play, seized operation, or damage to the clutch or decoupling mechanism. Use the appropriate alternator pulley removal and installation tools to prevent damage to the alternator shaft and internal components.
Ensure the replacement pulley matches the original pulley type, groove count, outside diameter, shaft connection, thread specifications, and rotational characteristics. Overrunning clutch pulleys and overrunning decoupler pulleys are not automatically interchangeable.
Always verify the Lester number, OEM alternator number, alternator series, pulley specifications, cross-reference numbers, and product photos before ordering. Follow the applicable manufacturer's installation and torque specifications.
After installation and reassembly, inspect pulley alignment, verify proper belt operation, and bench-test the alternator to confirm charging output and overall operation before returning it to service.
While You're Rebuilding
When replacing an alternator clutch / decoupler pulley, consider inspecting other components that may require replacement:
Important: Components listed above are inspection recommendations and are sold separately unless specifically stated otherwise in the product description.
Why Buy From R&C AUTO ELECTRIC PARTS?
R&C AUTO ELECTRIC PARTS specializes in alternator and starter rebuilding components for professional rebuilders, repair shops, automotive technicians, and DIY enthusiasts. Our extensive catalog includes thousands of OEM and aftermarket electrical components backed by detailed specifications and cross-reference information to help simplify part identification and reduce ordering mistakes.
Disclaimer
Compatibility information is provided as a reference only. Manufacturing revisions, production changes, and previous rebuilding modifications may affect alternator clutch / decoupler pulley compatibility. Always compare the Lester number, OEM alternator number, alternator series, pulley type, groove count, outside diameter, shaft connection, specifications, cross-reference numbers, and product photographs before ordering.
Overrunning clutch pulleys (OAP) and overrunning decoupler pulleys (OAD) are different designs and should not be considered interchangeable unless specifically approved for the application.
This listing is for the aftermarket alternator clutch / decoupler pulley only unless otherwise specified in the product description. If you are unsure about compatibility or product specifications, contact R&C AUTO ELECTRIC PARTS before ordering.