ZF 4699.804.098 GK25 | OEM Genuine Part

Overview

The ZF 4699.804.098 GK25 is a precision-engineered gearshift component designed for heavy-duty construction machinery transmissions. This OEM genuine part serves as the primary actuation mechanism within the valve body assembly, converting hydraulic pilot pressure into precise mechanical movement for clutch engagement. Positioned directly within the transmission control unit, the GK25 ensures reliable gear selection under extreme load conditions. The SKU 4699.804.098 is manufactured to ZF’s original specifications, guaranteeing exact fitment and long service life in demanding off-highway applications.

Symptoms of Failure

• Delayed or harsh gear engagement – When the GK25 wears, hydraulic pressure modulation becomes erratic, causing noticeable lag or jarring shifts during operation.
• Intermittent gear slipping under load – A failing unit cannot maintain consistent clutch pressure, leading to power loss on inclines or during heavy digging cycles.
• Transmission fluid contamination – Internal wear particles from the GK25 can migrate into the oil circuit, accelerating damage to seals and bearings.
• Unusual hydraulic noise – Worn spools or bores produce a distinct whining or chattering sound from the valve body area during shift events.

Technical Specifications

Compatibility

This GK25 shift component is engineered for ZF’s WG-series powershift transmissions commonly found in wheel loaders, excavators, and telehandlers. It directly fits the following models: WG180, WG200, WG210, and WG250. The part also integrates with select ErgoPower and Ecomat variants that share the same valve body architecture. Always verify your transmission serial number against ZF’s cross-reference before ordering.

During installation, the GK25 works in conjunction with several surrounding components. The 4699101043 HOUSING provides the structural enclosure for the shift assembly, while the 4699301106 HOUSING supports the adjacent hydraulic circuits. The 4699301015 HOUSING COVER seals the valve body top, and the 4699301085 COVER protects the shift mechanism from debris ingress. Replacing these units simultaneously is recommended to prevent premature wear recurrence.

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