ZF 4699.823.055 GP21 | OEM Genuine Part

Overview

The ZF 4699.823.055 GP21 is a high-precision OEM genuine part engineered for the planetary gear train assembly within ZF heavy-duty transmissions. This component, identified by SKU 4699.823.055, functions as a critical interface element that manages torque distribution and rotational alignment between the clutch pack and the output shaft. Located in the forward section of the transmission housing, the GP21 ensures smooth power flow during gear engagement under extreme load conditions. When paired with the 4699100019: BASIC PARTS kit, it forms the foundational assembly for reliable operation in construction machinery.

Symptoms of Failure

• Erratic gear engagement under load: When the 4699.823.055 wears, operators often report delayed or harsh shifting, especially when moving from neutral to drive in excavators or wheel loaders.
• Metallic grinding noise during deceleration: A distinct whining or grinding sound from the transmission bell housing indicates surface fatigue on the GP21 splines or bearing seats.
• Transmission fluid contamination with bronze particles: Worn bushings on this part shed fine metallic debris into the oil, detectable during routine filter inspections.
• Intermittent loss of drive in forward gears: The part’s failure to maintain concentric alignment can cause the clutch pack to slip, resulting in temporary power loss under heavy torque.

Technical Specifications

Compatibility

This OEM genuine GP21 is designed for integration into ZF WG-series powershift transmissions commonly used in construction machinery. It is a direct fit for the WG180, WG200, and WG211 transmission models. The part also appears in select variants of the WG150 series where planetary gear reduction is required. For proper installation, ensure the 4699300139: HOUSING is free of cracks and that the 4699300156: GEAR SHAFT splines are inspected for wear. The assembly must be torqued in sequence with the 4699300127: PLANET CARRIER to prevent axial play.

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