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Description
4230 640 5804 STIHL Gearbox Cover – Genuine OEM Blade Drive Gear Part
The STIHL Gearbox Cover (4230 640 5804) is a genuine OEM component designed to protect and enclose the blade drive gear assembly on select STIHL adjustable hedge trimmers and KombiSystem attachments. This cover secures the gearbox housing and helps protect internal gears from debris, contamination, and damage.
Over time, gearbox covers may crack, warp, or wear due to vibration, impact, or prolonged use in demanding cutting conditions. A damaged cover can allow dirt or debris into the gear assembly, potentially leading to premature gear wear or failure. Replacing it with the correct OEM part restores proper protection and sealing without replacing the entire gearbox assembly.
Manufactured to STIHL factory specifications, this genuine gearbox cover ensures precise fitment, secure mounting, and long-term durability under professional operating conditions.
Product Details
OEM Part Number: 4230 640 5804
Brand: STIHL (Genuine OEM)
Part Type: Gearbox Cover
Application: Blade drive gear assembly (adjustable 135° units)
Condition: New Genuine OEM Part
Function
This STIHL gearbox cover is designed to:
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Enclose and protect the blade drive gear assembly
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Prevent debris contamination inside the gearbox
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Maintain proper gear lubrication containment
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Provide structural support to the gear housing
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Replace cracked, damaged, or worn gearbox covers
⚠️ A damaged gearbox cover can allow contamination that may cause premature gear wear or failure.
Verify Fitment (Recommended)
Before ordering, confirm:
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OEM part number 4230 640 5804
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Your unit model matches those listed below
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Application matches your STIHL illustrated parts diagram
⚠️ Gearbox components are model-specific — always verify by OEM part number and equipment type.
Compatibility
This OEM gearbox cover fits STIHL adjustable hedge trimmers and KombiSystem attachments with 135° blade drive gear assemblies, including:
Adjustable Hedge Trimmers / Kombi Attachments (135°)
FH 135° (Blade drive gear, adjustable thru 135°)
FH-KM 135° (Blade drive gear, adjustable thru 135°)
HL 75 (Blade drive gear, adjustable thru 135°)
HL 75 K (Blade drive gear, adjustable thru 135°)
HL 100 (Blade drive gear, adjustable thru 135°)
HL 100 K (Blade drive gear, adjustable thru 135°)
HL 135° (Blade drive gear, adjustable thru 135°)
HL-KM 135° (Blade drive gear, adjustable thru 135°)
(Exact fitment depends on production version — always verify using OEM parts diagram.)
Installation Notes
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Remove blade assembly cover as required
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Access gearbox housing
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Remove damaged gearbox cover carefully
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Inspect gears and lubrication before reassembly
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Install new cover and tighten fasteners to specification
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Verify proper blade movement after installation
⚠️ Gearbox service should be performed carefully to maintain correct gear alignment and lubrication.
Maintenance Tips
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Inspect gearbox housing for cracks or oil leaks
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Keep blade drive gear assembly properly lubricated
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Avoid impact with hard objects that may damage housing
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Always use genuine STIHL OEM gearbox components for correct fit and durability
