ZF 4699.004.008 GK25 | OEM Genuine Part

Overview

The ZF 4699.004.008 GK25 is a precision-engineered gearshift component designed for the internal valve body assembly of heavy-duty ZF powershift transmissions. This OEM genuine part, identified by SKU 4699.004.008, controls hydraulic flow direction to engage specific gear ratios in construction machinery. It sits within the transmission control module, interacting directly with the main housing to regulate clutch pack pressure. For optimal sealing integrity, this component is frequently replaced alongside the 4699101043 HOUSING and the 4699301106 HOUSING during a full valve body overhaul.

Symptoms of Failure

• Delayed or harsh gear engagement: When the GK25 wears, hydraulic timing is disrupted, causing a noticeable lag or jarring shift when moving from neutral to drive.
• Intermittent gear slippage under load: A worn 4699.004.008 can cause the transmission to momentarily lose power during heavy digging or grading operations.
• Hydraulic fluid contamination: Internal wear particles from this part can circulate through the system, often requiring replacement of the 0634303980 O-RING and a full fluid flush.
• Erratic shifting patterns: The transmission may skip gears or fail to hold a selected gear, particularly in cold operating conditions.

Technical Specifications

Compatibility

This genuine ZF part is specifically designed for the GK25 shift valve assembly used in the following transmission models: WG180, WG200, WG210, and WG250. It is also compatible with certain variants of the Ecomat 4HP and 6HP series found in wheel loaders and excavators. When servicing these transmissions, always inspect the 4699301015 HOUSING COVER for cracks and verify the 4699301085 COVER is torqued to factory specifications to prevent cross-threading.

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