ZF 4699.804.087 GK25 | OEM Genuine Part

Overview

The ZF 4699.804.087 GK25 is a precision-engineered OEM genuine part designed for the hydraulic control system within heavy-duty ZF transmissions. This component, identified by SKU 4699.804.087, functions as a critical valve or actuation element that modulates oil flow to clutch packs and planetary gear sets. Located in the valve body assembly of construction machinery transmissions, it ensures precise shift timing and pressure regulation. When paired with the 4699101043 HOUSING, it forms a sealed unit that directs hydraulic fluid under high pressure. The GK25 designation indicates its specific calibration for torque capacity and response characteristics in off-highway applications.

Symptoms of Failure

• Erratic or delayed gear engagement – When the 4699.804.087 wears internally, operators may experience hesitation when shifting from neutral to forward or reverse, especially under load.
• Transmission overheating – A failing GK25 can cause continuous hydraulic slippage, generating excess heat that triggers warning lights or reduces machine performance.
• Oil contamination from internal debris – Worn sealing surfaces on this part allow metal particles to circulate, often detected during routine oil analysis or when inspecting the 0634303980 O-RING for degradation.
• Intermittent loss of drive pressure – Operators may notice sudden drops in hydraulic pressure on gauges, particularly during incline operation or heavy digging cycles.

Technical Specifications

Compatibility

This OEM genuine part is engineered for ZF WG series transmissions commonly used in construction machinery. It is directly compatible with the WG180, WG200, and WG210 models, which power wheel loaders, excavators, and telehandlers from manufacturers like Liebherr, Volvo, and Caterpillar. The GK25 also fits select Ecomat 4HP and 6HP variants where hydraulic modulation is required. For proper installation, ensure the 4699301106 HOUSING and 4699301015 HOUSING COVER are free of scoring. The 4699301085 COVER must be torqued to factory specifications to prevent cross-threading.

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