ZF 0737.835.166 UNION SCREW for WG200 | OEM Genuine Part

Overview

The ZF 0737.835.166 UNION SCREW is a precision-engineered hydraulic fitting designed for the WG 200 series powershift transmissions. This OEM genuine part functions as a critical sealing and connection point within the transmission’s oil supply circuit, ensuring secure attachment of fluid lines to the valve body or housing assembly. By maintaining proper hydraulic pressure, the union screw prevents fluid bypass and supports consistent clutch engagement. The SKU 0737.835.166 is manufactured to ZF’s exacting tolerances, making it a direct replacement for worn or damaged fittings in heavy-duty industrial drivetrains.

Symptoms of Failure

When the ZF 0737.835.166 union screw degrades, operators may notice external transmission oil leaks at the fitting point, often accompanied by a gradual drop in fluid level. A second symptom is erratic gear engagement or slipping under load, caused by insufficient hydraulic pressure reaching the clutch packs. Third, aeration or foaming of transmission fluid can occur if the union screw allows air ingress, leading to noisy operation and reduced torque capacity. Finally, visible corrosion or thread damage on the screw body itself indicates imminent failure, especially in high-vibration environments.

Technical Specifications

Compatibility

This union screw is primarily specified for the ZF WG 200 series transmissions, including models WG200, WG180, and WG210. It also fits select WG 150 variants where the hydraulic circuit uses identical port dimensions. The part interfaces directly with the TRANSMISSION HOUSING (4644101176) and the TRANSMISSION HOUSING (4644301371), ensuring a leak-free seal. For identification purposes, the TYPE PLATE (0730365067) should be consulted to verify transmission series before installation. The screw is secured using the GROOVED STUD (0631311009) in certain assembly configurations.

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