ZF 4644.353.021 SPUR GEAR for WG180 | OEM Genuine Part

Overview

The ZF 4644.353.021 SPUR GEAR is a critical power transmission component engineered specifically for the WG 180 series transmissions. This OEM genuine part, identified by SKU 4644.353.021, sits within the planetary gear set assembly where it directly engages with the output shaft to transfer rotational force from the torque converter to the driveline. By maintaining precise tooth geometry and surface hardness, this spur gear ensures smooth torque delivery under heavy loads, reducing vibration and wear across the entire drivetrain. It works in concert with the 4644105413: DISCONNECTION mechanism to enable seamless gear changes, while the 4642303093: OUTPUT FLANGE provides the final interface to the driveshaft.

Symptoms of Failure

When the ZF 4644.353.021 spur gear begins to wear, operators typically notice these specific failure indicators:

• Audible whining or grinding noise during acceleration – A high-pitched sound from the transmission housing, especially under load, indicates tooth surface pitting or chipping.
• Intermittent gear slippage in forward gears – The transmission may momentarily lose power delivery, often accompanied by a brief RPM flare, as the spur gear fails to maintain positive engagement.
• Metallic debris in transmission fluid – Small, silver-colored particles found during routine oil changes signal that the gear teeth are spalling or fracturing.
• Vibration through the chassis at specific speeds – A rhythmic shudder, typically between 30-50 km/h, points to uneven wear on the gear’s helical teeth.

Technical Specifications

Compatibility

This spur gear is primarily designed for the ZF WG 180 series transmissions, which are widely used in medium-duty commercial vehicles, buses, and off-highway equipment. Based on its tooth profile and spline dimensions, the 4644.353.021 part is also compatible with the ZF WG 200 series and certain variants of the ZF WG 150 series where the planetary carrier assembly shares identical geometry. It integrates directly with the 4644101222: TRANSMISSION HOUSING and is secured using the 0636021010: HEXAGON SCREW fasteners. Always verify the spline count and gear ratio against your specific transmission serial number before installation.

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