ZF 4644.306.300 PISTON for WG 180/WG 200 | OEM Genuine Part

Overview

The ZF 4644.306.300 PISTON is a critical hydraulic actuation component engineered for the WG 180 and WG 200 series transmissions. This OEM genuine part functions as the primary force-transfer element within the clutch or brake piston assembly, converting hydraulic pressure into mechanical movement to engage gear sets. Positioned inside the transmission housing, the piston must maintain a precise seal and smooth axial travel to ensure proper shift timing. The SKU 4644.306.300 is manufactured to ZF’s exacting tolerances, using high-strength materials to withstand repeated high-pressure cycles and thermal expansion. When this piston degrades, it directly compromises the hydraulic circuit, leading to delayed engagement or pressure loss. For a complete rebuild, always inspect the 4644101164: TRANSMISSION HOUSING and 4644301371: TRANSMISSION HOUSING for wear or scoring that could damage the new piston.

Symptoms of Failure

• Erratic gear engagement or slipping under load: A worn 4644.306.300 piston cannot maintain consistent hydraulic pressure, causing the transmission to slip out of gear during acceleration or uphill driving.
• Oil leaks around the transmission bell housing: Cracks or scoring on the piston surface allow transmission fluid to bypass the seal, resulting in visible drips or puddles beneath the vehicle.
• Delayed or harsh shifting: When the piston sticks or fails to return fully, shift timing becomes unpredictable, often producing a noticeable clunk or lag between gear changes.
• Low transmission fluid pressure warnings: A failing piston reduces overall system pressure, triggering diagnostic trouble codes (DTCs) related to clutch or solenoid performance.

Technical Specifications

Compatibility

This piston is specifically designed for the ZF WG 180 and WG 200 series transmissions, which are widely used in heavy-duty trucks, buses, and off-highway equipment. It is a direct replacement for the original factory component in these models. While the piston itself is model-specific, it frequently requires replacement alongside the 0730365067: TYPE PLATE for correct identification and the 0631311009: GROOVED STUD for secure mounting. Always verify the transmission serial number against the type plate before ordering.

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