ZF 4143.315.028 SUN GEAR for WG100/WG130/WG131 | OEM Genuine Part

Overview

The ZF 4143.315.028 SUN GEAR is a critical planetary component engineered for the WG100, WG130, and WG131 transmission series. This OEM genuine part functions as the central driving gear within the planetary gearset, transferring torque from the input shaft to the planetary pinions. As a high-precision hardened steel component, it directly influences gear ratio stability and load distribution. The SKU 4143.315.028 is machined to exact ZF tolerances to ensure concentric rotation and minimal backlash. When installed, it meshes with the planetary carrier and ring gear, making it essential for smooth power flow under heavy-duty industrial applications.

Symptoms of Failure

• Erratic gear engagement or slipping – Worn sun gear teeth cause intermittent power loss during acceleration or under load, often accompanied by a grinding noise.
• Metallic debris in transmission fluid – Flaking or pitting on the sun gear surface generates fine metal particles, visible during oil changes or filter inspections.
• Vibration and whining noise – Uneven tooth wear creates harmonic vibrations that intensify at specific RPM ranges, indicating imminent gear failure.
• Delayed or harsh shifting – Damaged sun gear teeth disrupt planetary gearset timing, leading to abrupt clutch engagement or hesitation between gears.

Technical Specifications

Compatibility

This sun gear is directly compatible with ZF WG100, WG130, and WG131 transmissions. It also fits select HL 100 Series and HL 270 Series gearboxes that share the same planetary carrier architecture. While primarily designed for WG-series units, it may be cross-referenced in older ZF WG180 and WG200 models where the planetary gearset dimensions match. Always verify tooth count and spline diameter against your existing sun gear before installation.

Installation Context

Replacing the sun gear requires disassembly of the planetary assembly. During this process, inspect the 4143101009: HOUSING and 4143301025: HOUSING for cracks or wear. The 0634313603: O-RING must be replaced to prevent fluid bypass, and the 4475280018: SCREW PLUG should be torqued to factory specifications to avoid leaks. Proper alignment of these components ensures the sun gear operates within its designed clearance.

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