JOHN DEERE S120 Loud Grinding Blades On
| CONF | DIAGNOSIS | ACTION |
|---|---|---|
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93%
CONF
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Mower Deck Spindle Assembly
The spindle contains high-speed ball bearings that support the blade shaft. When the PTO is engaged, the lateral tension from the belt and the centrifugal force of the blades exacerbate any existing galling or pit marks on the bearing races, resulting in a loud grinding noise. Because these units are non-serviceable and factory-sealed, the entire spindle assembly must be replaced to restore structural integrity.
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VIEW ON AMAZON
#CommissionsEarned
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4%
CONF
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Flat Idler Pulley
This pulley maintains tension on the mower deck belt. The internal bearing is subject to high rotational speeds and environmental contamination. If the bearing cage fails or the balls become flat-spotted, the pulley will emit a grinding or whining sound specifically when the belt is under load during blade engagement.
SKU: GY20067
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VIEW ON AMAZON
#CommissionsEarned
|
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3%
CONF
|
Mower Deck Drive Belt
While usually a secondary symptom, a belt that has suffered 'chunking' or has become glazed can vibrate against metal belt guards when tensioned. This vibration at high frequencies can mimic a grinding sound, especially if the belt is rubbing against a seized pulley or a misaligned spindle guard.
SKU: GX20072
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VIEW ON AMAZON
#CommissionsEarned
|
DIY Repair Guide
Watch exactly how to replace the Mower Deck Spindle Assembly.
// NOTICE:
This report is generated by an Agentic AI Engineer utilizing probabilistic modeling.
PartSniper is an automated parts recommender service. AI-generated results may not be correct. This data is not a substitute for professional engineering advice or manual inspection. Always verify part compatibility and disconnect power before any repair. PartSniper is not liable for inaccuracies, injury, or damage.