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Description
4243 740 5004 STIHL HL-KM 145° Gear Head Assembly – Genuine OEM Adjustable Angle Drive Part
The STIHL HL-KM 145° Gear Head Assembly (4243 740 5004) is a genuine OEM gearbox and cutting head component designed for the STIHL HL-KM 145° long-reach hedge trimmer KombiTool attachment. This adjustable-angle gear head allows trimming at multiple working positions, making it ideal for professional hedge shaping, overhead cutting, and hard-to-reach landscaping applications.
The gear head assembly is a critical drivetrain component that transfers rotational power from the internal drive shaft to the cutter bar system. Over time, internal gears and bearings may wear due to heavy commercial use, insufficient lubrication, vibration, or impact damage. A worn or failing gear head may cause grinding noise, reduced blade speed, gear slipping, excessive vibration, or complete loss of cutting function.
Replacing the gear head with the correct genuine STIHL OEM part restores factory performance, smooth blade operation, and long-term durability without replacing the entire attachment.
Manufactured to STIHL factory specifications, this OEM gear head ensures precise fitment, reliable gear engagement, and dependable cutting performance under demanding working conditions.
Product Details
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OEM Part Number: 4243 740 5004
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Brand: STIHL (Genuine OEM)
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Part Type: Gear Head / Angle Drive Assembly
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Angle Configuration: 145° Adjustable Head
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Application: Power transmission to cutter bar system
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Condition: New Genuine OEM Part
Function
This STIHL HL-KM 145° gear head assembly is designed to:
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Transfer driveline power to the hedge trimmer blade system
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Support adjustable cutting angles up to 145°
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Maintain smooth and consistent cutter bar motion
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Replace worn, noisy, or damaged gear drive heads
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Restore safe and reliable long-reach trimming performance
⚠️ A failing gear head can cause vibration, noise, or complete blade drive failure.
Verify Fitment (Recommended)
Before ordering, confirm:
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OEM part number 4243 740 5004
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Your attachment is the HL-KM 145° adjustable-angle version
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Gear head configuration matches your drive tube assembly
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Your unit model matches those listed below
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Fitment is verified using your STIHL illustrated parts diagram
⚠️ Gear heads are model-specific — always verify by OEM part number.
Compatibility
This OEM gear head assembly fits select STIHL Kombi hedge trimmer attachments, including:
KombiTool Hedge Trimmer Attachments
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HL-KM 145° Long-Reach Hedge Trimmer Attachment
(Exact fitment depends on production version — always confirm using OEM parts diagram.)
Installation Notes
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Disconnect power source before servicing
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Remove cutter bar and drive tube components as required
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Detach worn gear head assembly carefully
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Install new OEM gear head ensuring correct spline engagement
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Reassemble housing and torque fasteners to specification
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Test blade rotation, gearbox function, and angle adjustment
⚠️ Gear head replacement should be performed by a qualified technician to ensure proper alignment and safe operation.
Maintenance Tips
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Lubricate the gearbox regularly with STIHL-approved grease
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Inspect for vibration or unusual noise during operation
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Avoid impact damage to the cutter bar and head assembly
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Replace worn gear heads promptly to prevent driveline failure
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Always use genuine STIHL OEM parts for correct fit and durability

