ZF 4644.330.293 DIAPHRAGM for WG200 | OEM Genuine Part

Overview

The ZF 4644.330.293 DIAPHRAGM is a critical pneumatic control element engineered for the WG 200 Series transmission family. This OEM genuine part functions as a flexible sealing and actuation membrane within the transmission’s hydraulic control unit, precisely regulating air pressure to govern clutch pack engagement and gear selection. Positioned between the valve body and the shift actuator housing, the diaphragm ensures a leak-free barrier that maintains consistent pressure differentials during operation. The SKU 4644.330.293 is manufactured to ZF’s original specifications, guaranteeing exact fitment and reliable service life in demanding commercial vehicle applications.

Symptoms of Failure

• Erratic gear engagement or delayed shifting – A worn or torn diaphragm cannot maintain proper pneumatic pressure, causing hesitation or harsh shifts when the transmission attempts to change gears.
• Oil or air leaks near the shift actuator housing – Deterioration of the rubber material leads to visible fluid seepage around the HOUSING interface, often accompanied by a drop in system pressure.
• Transmission slipping under load – Loss of diaphragm integrity reduces clutch holding force, resulting in RPM flare without corresponding vehicle acceleration, especially during uphill climbs.
• Intermittent neutral or failure to hold park – Advanced wear can cause the diaphragm to rupture completely, leading to sudden loss of drive or inability to engage reverse.

Technical Specifications

Compatibility

This diaphragm is specifically designed for the ZF WG 200 Series, including models WG180, WG200, and WG210. It also fits select variants of the ZF 6HP and 8HP automatic transmissions used in medium-duty trucks and buses. The part integrates directly with the TRANSMISSION HOUSING and is secured using the GROOVED STUD for precise alignment. Always verify the TYPE PLATE on your transmission to confirm model designation before installation.

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