ZF 4644.230.027 DIAPHRAGM for WG200/WG201 | OEM Genuine Part

Overview

The ZF 4644.230.027 DIAPHRAGM is a critical pneumatic actuation component engineered for the WG 200 and WG 201 series transmissions. 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 gears. Positioned between the actuator housing and the piston, the diaphragm ensures precise pressure regulation and prevents cross-contamination of transmission fluid. The SKU 4644.230.027 is manufactured to exact ZF tolerances, guaranteeing a perfect seal and consistent performance in heavy-duty applications. When paired with a robust TRANSMISSION HOUSING, this diaphragm maintains the integrity of the entire shift system.

Symptoms of Failure

• Erratic gear engagement or delayed shifting: A worn diaphragm loses its ability to hold pneumatic pressure, causing sluggish or unpredictable gear changes, especially under load.
• External air or oil leaks near the actuator: Cracks or tears in the rubber material allow pressurized air or transmission fluid to escape, often visible as wet spots around the HOUSING assembly.
• Transmission slipping in higher gears: As the diaphragm deteriorates, insufficient clamping force leads to clutch pack slippage, reducing torque transfer and causing overheating.
• Audible hissing from the transmission: A perforated diaphragm produces a distinct air leak sound during shift events, indicating immediate replacement is necessary.

Technical Specifications

Compatibility

This diaphragm is specifically designed for ZF WG series transmissions, including the WG180, WG200, and WG201 models. It is a direct replacement for units equipped with pneumatic shift actuators. The part also integrates with the TYPE PLATE for correct identification and the GROOVED STUD for secure mounting. Always verify your transmission serial number against the WG200 or WG201 series to ensure fitment.

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