ZF 4644.302.023 SPUR GEAR for WG181 | OEM Genuine Part

Overview

The ZF 4644.302.023 SPUR GEAR is a critical power transmission component engineered specifically for the WG181 series transmission. This OEM genuine part, identified by SKU 4644.302.023, sits within the intermediate shaft assembly, where it meshes directly with the main drive gear to transfer torque from the engine to the planetary gear sets. Precision-ground tooth profiles ensure minimal backlash and quiet operation under heavy load. This spur gear is often replaced in conjunction with the 4644101047 TRANSMISSION HOUSING and the 4644301380 HOUSING during a major overhaul to maintain gear alignment and prevent premature wear.

Symptoms of Failure

• Whining or grinding noise during gear engagement: As the spur gear teeth wear or develop pitting, a distinct metallic whine or grinding sound becomes audible, especially under load or during deceleration.
• Vibration in the driveline at specific RPM ranges: Worn tooth profiles cause uneven power transfer, leading to noticeable vibration through the chassis when the transmission is in a specific gear range.
• Metal particles in transmission fluid: Flaking or spalling of the gear surface introduces ferrous debris into the oil, which can be detected during routine fluid analysis or when draining the sump.
• Intermittent gear slipping or harsh shifting: Excessive backlash from a worn spur gear can confuse the hydraulic control system, resulting in delayed engagement or unexpected slipping between shifts.

Technical Specifications

Compatibility

This spur gear is primarily designed for the ZF WG181 series transmission, which is widely used in medium-duty trucks, buses, and off-highway vehicles. Based on its tooth geometry and shaft interface, it is also compatible with the ZF WG180 and WG200 series transmissions that share the same intermediate shaft layout. Always verify the gear ratio and shaft spline count before installation. The 4644301189 THREADED BUSH and 0730365067 TYPE PLATE are commonly replaced alongside this gear to ensure correct axial positioning and identification.

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