ZF 4699.804.109 GK25 | OEM Genuine Part

Overview

The ZF 4699.804.109 GK25 is a precision-engineered gear kit designed for heavy-duty construction machinery transmissions. This OEM genuine part serves as the primary reduction gearset within the ZF GK25 series, directly controlling torque multiplication and output speed in wheel loaders, graders, and material handlers. As a core rotating assembly, it interfaces with the 4699004015: GK25 main gear set to ensure smooth power delivery under extreme loads. The SKU 4699.804.109 is manufactured to ZF’s original tolerances, guaranteeing a direct replacement without modification.

Symptoms of Failure

When the 4699.804.109 gear kit begins to fail, operators typically notice these specific warning signs:

• Erratic gear engagement under load: The transmission may hesitate or grind when shifting between forward and reverse, particularly during high-torque operations like digging or pushing.
• Metallic whining or chattering noise: Worn gear teeth produce a distinct high-pitched sound from the transmission housing, often worsening as hydraulic pressure increases.
• Oil contamination with metal particles: Magnetic drain plugs or oil filters will show fine silver or steel debris, indicating gear surface spalling or pitting.
• Intermittent loss of drive in specific gears: The machine may suddenly lose power to the wheels, then regain it, as damaged teeth skip under load.

Technical Specifications

Compatibility

This gear kit is engineered for ZF’s WG series powershift transmissions commonly found in construction equipment. It is a direct fit for the following models:

• ZF WG180 (all variants)
• ZF WG200 (series 2 and 3)
• ZF WG210 (early production)
• ZF 4WG-200 (with GK25 planetary set)

During installation, always inspect the mating 4699101025: HOUSING for cracks or wear, and verify the 4699102063: INPUT shaft splines are free of galling. The 4699103026: OUTPUT flange must be torqued to factory specifications to prevent axial play.

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