ZF 4699.825.221 GP25 | OEM Genuine Part

Overview

The ZF 4699.825.221 GP25 is a critical OEM genuine gear assembly designed for high-torque applications in construction machinery transmissions. Positioned within the planetary gear set of ZF’s heavy-duty powertrains, this component facilitates smooth power transfer and torque multiplication under extreme loads. The SKU 4699.825.221 specifically denotes a factory-spec GP25 unit, engineered to maintain precise gear mesh alignment and reduce internal friction. When paired with the 4699025084 GP25 companion part, it forms a matched set that ensures consistent performance in demanding environments like wheel loaders and excavators.

Symptoms of Failure

When the ZF 4699.825.221 GP25 wears out, operators often notice these specific failure indicators:

• Erratic gear engagement during shifting — A delayed or harsh “clunk” when transitioning between forward and reverse gears, often caused by worn teeth on the GP25 assembly.
• Metallic whining noise from the transmission housing — A high-pitched sound that intensifies under load, indicating bearing or gear surface degradation within the 4699.825.221 unit.
• Oil contamination with metallic particles — Visible silver or bronze debris in the transmission fluid, a direct sign of GP25 gear spalling or pitting.
• Intermittent loss of drive power — The machine hesitates or fails to move under load, particularly when climbing grades, due to the GP25 slipping within its planetary carrier.

Technical Specifications

Compatibility

This GP25 gear assembly is engineered for integration into ZF’s WG series powershift transmissions. It is a direct fit for the WG180 and WG200 models commonly used in construction machinery. The 4699.825.221 also appears in select WG150 and WG250 variants where the planetary gear set requires the 25-tooth planet gear configuration. For proper installation, this part must be aligned with the 4699101155 HOUSING that encloses the planetary carrier, and it interfaces directly with the 4699102095 INPUT shaft and the 4699103075 OUTPUT shaft assembly.

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