ZF 4108.303.290 RING | OEM Genuine Part

Overview

The ZF 4108.303.290 RING is a precision-engineered OEM genuine component designed for the internal clutch pack and planetary gear assemblies within heavy-duty ZF transmissions. This ring functions as a critical load-bearing and alignment surface, ensuring proper gear engagement and hydraulic pressure containment. Located within the rotating drum assembly, the SKU 4108.303.290 directly interfaces with the HOUSING and the HOUSING to maintain concentricity during high-torque operations in construction machinery. Without this ring, the transmission cannot maintain the necessary clamping force for power transfer.

Symptoms of Failure

• Intermittent gear slipping under load: When the 4108.303.290 ring wears, it fails to provide adequate backing for the clutch plates, causing the transmission to slip when climbing grades or moving heavy material.
• Metallic debris in transmission fluid: A worn ring sheds fine steel particles into the hydraulic circuit, often visible during routine oil changes or when inspecting the DRAIN VALVE magnet.
• Delayed or harsh shifting: Loss of ring thickness alters the piston stroke, resulting in sluggish engagement or abrupt gear changes that stress the BEARING COVER assembly.
• Hydraulic pressure drop: A cracked or deformed ring allows internal leakage, reducing system pressure below the 18-22 bar specification required for proper clutch lockup.

Technical Specifications

Compatibility

This ring is a direct-fit OEM replacement for ZF WG180, WG200, and WG210 series transmissions commonly used in wheel loaders, telehandlers, and excavators. It also applies to the 4WG-200 and 6WG-200 variants found in construction machinery from 2005 onward. Always verify the serial number on your transmission housing before installation. The ring seats against the BEARING COVER and must be paired with a new GASKET and SHAFT SEAL to prevent fluid bypass.

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