ZF 2098.304.039 SPUR GEAR for WG100/WG130/WG131 | OEM Genuine Part

Overview

The ZF 2098.304.039 SPUR GEAR is a precision-engineered component designed for the auxiliary drive and power take-off (PTO) circuits within ZF WG100, WG130, and WG131 transmissions. This OEM genuine part, identified by SKU 2098.304.039, transfers rotational force between parallel shafts, ensuring smooth engagement and disengagement of auxiliary systems. Mounted directly on the countershaft assembly, it works in concert with the 2098117002: HOUSING to maintain correct gear mesh alignment and oil flow distribution. The spur gear’s hardened tooth profile is critical for handling high torque loads without deformation, directly influencing transmission longevity and operational reliability.

Symptoms of Failure

• Whining or grinding noise during PTO engagement: Worn or chipped teeth on the 2098.304.039 spur gear produce a distinct metallic whine, especially under load. This often indicates surface fatigue or pitting, which accelerates if the 0636103300: STUD securing the gear assembly is loose.
• Intermittent power loss to auxiliary equipment: A failing spur gear may skip teeth under torque, causing sudden drops in hydraulic pump or winch output. This symptom is frequently misdiagnosed as a clutch issue, but inspection of the gear and its mating 0637101164: HEXAGON NUT often reveals the root cause.
• Metallic debris in transmission fluid: Flaking or spalling of the gear’s hardened surface introduces ferrous particles into the oil. This contamination can clog the 2098301052: REAR AXLE HOUS. oil passages, leading to broader lubrication failures.
• Vibration at specific RPM ranges: Uneven tooth wear or a bent shaft from impact loads creates harmonic vibrations. This is particularly noticeable when the transmission is under partial load, indicating the spur gear requires immediate replacement.

Technical Specifications

Compatibility

This spur gear is specifically engineered for the ZF WG100, WG130, and WG131 series transmissions. These models are commonly found in medium-duty trucks, agricultural tractors, and construction loaders. The gear interfaces directly with the countershaft and is secured by the 0636103300: STUD and 0637101164: HEXAGON NUT. While primarily designed for WG100/WG130/WG131, it may also fit select WG180 and WG200 variants with identical auxiliary drive configurations—always verify spline count and bore dimensions before installation. The gear’s housing is sealed using the 2098117002: HOUSING and 2098301052: REAR AXLE HOUS. to prevent contamination.

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