ZF 4644.323.004 SUN GEAR for WG200 | OEM Genuine Part

Overview

The ZF 4644.323.004 SUN GEAR is a critical planetary component engineered for the WG 200 series transmission. This OEM genuine part serves as the central gear within the planetary gearset, transferring torque from the input shaft to the planet gears. Positioned directly within the main drive assembly, the sun gear (SKU: 4644.323.004) must withstand extreme rotational forces and high thermal loads. When replacing this component, it is common to also inspect and replace the 4460165051: CONSOLE and the 4460368311: CONSOLE to ensure proper alignment and load distribution across the gearset.

Symptoms of Failure

• Whining or grinding noise during gear engagement: A worn sun gear produces a distinct high-pitched whine under load, often mistaken for bearing failure. This noise intensifies during acceleration or hill climbs.
• Intermittent gear slipping under torque: As the sun gear teeth wear unevenly, the transmission may momentarily lose power delivery, causing a “skip” sensation during shifting.
• Metallic debris in transmission fluid: Flaking or pitting on the sun gear surface releases fine steel particles into the oil, visible during fluid changes or on the magnetic drain plug.
• Hard shifting or delayed engagement: Excessive backlash from a damaged sun gear forces the transmission to hunt for gears, particularly between 2nd and 3rd in WG200 units.

Technical Specifications

Compatibility

This sun gear is primarily designed for the ZF WG 200 series, including the WG200, WG210, and WG180 variants. It is also compatible with select ZF Ecomat 4HP and 5HP models that share the same planetary carrier design. For precise fitment, always verify the transmission serial number. When servicing the planetary assembly, consider replacing the 0636011429: HEXAGON SCREW and the 0730100365: WASHER to prevent fastener fatigue and oil seepage at the carrier joint.

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