ZF 4699.823.009 GP21 | OEM Genuine Part

Overview

The ZF 4699.823.009 GP21 is a precision-engineered gear pump assembly designed for high-pressure hydraulic circuits within ZF powershift transmissions. This OEM genuine part, identified by SKU 4699.823.009, serves as the primary hydraulic power source, delivering consistent oil flow to actuate clutch packs and lubricate internal components. Mounted directly to the transmission housing, the GP21 pump draws fluid from the sump and pressurizes it for distribution. When paired with a HOUSING and BASIC PARTS, this unit ensures reliable torque converter fill and shift response in demanding construction machinery applications.

Symptoms of Failure

• Slow or erratic clutch engagement: A worn GP21 pump cannot maintain adequate pressure, causing delayed gear shifts or slipping under load. This is a common symptom when the pump gears or housing wear.
• Low transmission oil pressure warnings: If the pump fails to generate sufficient flow, dashboard pressure alerts or diagnostic codes will appear, often accompanied by overheating.
• Audible whining or grinding from the transmission: Cavitation or worn internal components produce a high-pitched noise, indicating the pump is struggling to draw oil or has damaged gears.
• Oil leaks near the pump mounting flange: Deteriorated seals or a cracked HOUSING allow fluid to escape, leading to low oil levels and eventual transmission failure.

Technical Specifications

Compatibility

This GP21 pump is engineered for ZF WG series powershift transmissions commonly used in wheel loaders, dozers, and telehandlers. It is a direct fit for the WG180 and WG200 models, as well as select variants of the WG150 and WG210 series. The pump interfaces with the GEAR SHAFT and PLANET CARRIER to synchronize hydraulic flow with mechanical power delivery. Always verify your transmission model and housing casting number before installation.

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