ZF 4139.330.349 DIAPHRAGM for WG150/WG200/WG201 | OEM Genuine Part

Overview

The ZF 4139.330.349 DIAPHRAGM is a critical pneumatic actuation component engineered for the WG150, WG200, and WG201 transmission series. This OEM genuine part functions as a flexible sealing membrane within the clutch or shift actuator assembly, converting air pressure into mechanical force to engage and disengage gear sets. The SKU 4139.330.349 ensures precise modulation of hydraulic circuits, directly influencing shift quality and torque delivery. Installed adjacent to the 4642101109: TRANSMISSION HOUSING, this diaphragm maintains system integrity by preventing cross-contamination between pneumatic and oil circuits.

Symptoms of Failure

• Delayed or harsh gear engagement – A ruptured diaphragm causes inconsistent air pressure, leading to “ZF transmission slipping under load” or abrupt shifts.
• External oil leaks near actuator housing – Worn material allows transmission fluid to bypass seals, often misdiagnosed as “WG200 series oil leak from shift cylinder.”
• Erratic clutch behavior – The part fails to hold pressure, resulting in “WG150 transmission shuddering on startup” or incomplete disengagement.
• Increased air consumption – A cracked diaphragm forces the compressor to cycle frequently, a classic sign of “pneumatic actuator failure in ZF WG201.”

Technical Specifications

Compatibility

This diaphragm is specifically validated for ZF WG150, WG200, and WG201 series transmissions used in industrial forklifts, reach stackers, and heavy-duty material handling equipment. It directly interfaces with the 0730365125: TYPE PLATE identification system and mounts via the 0631311009: GROOVED STUD assembly. While primarily designed for WG200 variants, cross-referencing with WG180 and WG210 models is possible when paired with the correct actuator cover. Always verify the diaphragm thickness against your existing unit before installation.

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