STIHL Gearbox Cover - 4243 640 5800

The STIHL Gearbox Cover (part number 4243 640 5800) functions as a direct-fit, original-equipment protective housing that seals internal drive transmissions against abrasive contaminants, moisture, and operational vibration. Engineered to replace compromised factory units, this component restores proper gearbox encapsulation and maintains manufacturer-specified tolerances without altering mounting hardware or service intervals.

Key Features

• Dimensionally matched to factory gearbox apertures for immediate bolt-on installation
• Preserves internal lubrication by blocking ingression of soil, water, and cut vegetation debris
• Chemical-resistant polymer construction withstands repeated exposure to fuels, oils, and hydraulic fluids
• Direct OEM replacement eliminates aftermarket adapter brackets or frame modifications

Product Details

• Brand: STIHL
• Original part reference: 4243 640 5800
• Application classification: Drive unit gearbox enclosure
• Fastener pattern: Identical to factory chassis mounting specifications
• Manufacturing compliance: Meets STIHL structural and vibration-damping requirements

Compatibility

• STIHL FS 700 R, FS 800 R, FS 900 R brushcutters
• STIHL KM 130 R, KM 160 R, KM 180 R multi-system power heads
• STIHL MS 661 C-M, MS 391 C-M pole saw adapter modules
• Select hedge-cutting and trimming attachment drive housings utilizing the same OEM gearbox architecture