ZF 4644.303.096 SPEEDOMETER WORM for WG181 | OEM Genuine Part

Overview

The ZF 4644.303.096 SPEEDOMETER WORM is a precision-machined component engineered specifically for the WG 181 series of heavy-duty transmissions. This OEM genuine part interfaces directly with the output shaft to generate the rotational signal required for accurate vehicle speed indication. Installed within the transmission housing, the worm gear engages with a complementary speedometer drive gear to convert mechanical rotation into a readable speed signal. The SKU 4644.303.096 is manufactured to ZF’s exacting tolerances, ensuring seamless integration and long service life in demanding industrial applications.

Symptoms of Failure

• Intermittent or erratic speedometer readings — A worn worm gear can cause the speedometer needle to fluctuate or drop to zero unexpectedly, especially during deceleration or at low speeds.
• Complete loss of speedometer function — When the worm’s teeth become stripped or excessively worn, the speedometer may stop working entirely, leaving the operator without critical vehicle speed data.
• Unusual transmission noise — A failing 4644.303.096 worm often produces a high-pitched whining or grinding sound from the rear of the transmission, particularly noticeable at highway speeds.
• Oil contamination from gear debris — As the worm deteriorates, metal particles can enter the transmission fluid, potentially damaging the TRANSMISSION HOUSING and other internal components.

Technical Specifications

Compatibility

This speedometer worm is primarily designed for the ZF WG 181 series transmissions. It is also compatible with the WG 180, WG 200, and WG 211 series models that utilize a similar speedometer drive configuration. The part fits transmissions produced between 1995 and 2015, though cross-referencing with your specific transmission serial number is recommended. When replacing this worm, always inspect the TRANSMISSION HOUSING for wear at the mounting bore, and verify the condition of the THREADED BUSH that secures the worm assembly. Additionally, the SCREW PLUG should be replaced to prevent fluid leaks at the access port.

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