ZF 4699.804.039 GK25 | OEM Genuine Part

Overview

The ZF 4699.804.039 GK25 is a precision-engineered OEM genuine part designed for heavy-duty construction machinery transmissions. This component functions as a critical shift element within the valve body assembly, regulating hydraulic flow to engage and disengage gear sets. The SKU 4699.804.039 is specifically calibrated for ZF’s powershift transmission series, ensuring precise clutch modulation under extreme load conditions. When installed alongside the 4699101043 HOUSING and 4699301106 HOUSING, this part forms the core hydraulic control unit that directs oil pressure to the correct clutch packs.

Symptoms of Failure

• Delayed gear engagement — When the GK25 wears, operators experience a noticeable lag between shifting and actual gear engagement, often accompanied by harsh clunking sounds.
• Intermittent transmission slipping — A worn 4699.804.039 causes pressure loss, leading to random gear slippage under heavy loads, particularly during uphill operation.
• Hydraulic fluid contamination — Internal wear particles from this part can circulate through the system, accelerating damage to the 4699301015 HOUSING COVER and 4699301085 COVER seals.
• Erratic shift patterns — The transmission may skip gears or fail to hold a selected gear, indicating the GK25 is no longer maintaining proper hydraulic balance.

Technical Specifications

Compatibility

This OEM genuine part is engineered for ZF powershift transmissions commonly found in construction machinery. It is directly compatible with the following ZF transmission models: WG180, WG200, WG210, and WG220. The 4699.804.039 GK25 also fits select variants of the ERGO and Powershift 2 series used in wheel loaders, graders, and telescopic handlers. Always verify your transmission serial number before ordering, as revisions may require updated housing components like the 4699301015 HOUSING COVER.

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