ZF 4642.306.091 PISTON for WG 150 | OEM Genuine Part

Overview

The ZF 4642.306.091 PISTON for WG 150 is a critical hydraulic actuation component engineered for precise clutch or brake application within the WG series automatic transmissions. This OEM genuine part, identified by SKU 4642.306.091, converts hydraulic pressure into linear mechanical force to engage specific gear sets. Located within the valve body or clutch drum assembly, this piston ensures smooth shift transitions and maintains consistent line pressure. When paired with a robust TRANSMISSION HOUSING, it forms a sealed hydraulic circuit essential for torque management.

Symptoms of Failure

• Delayed or harsh gear engagement: A worn or cracked piston causes slow clutch pack application, leading to jarring shifts when accelerating from a stop.
• Intermittent loss of drive in forward gears: Internal fluid bypass around the piston results in pressure drop, causing the transmission to momentarily slip under load.
• Hydraulic fluid contamination: Degraded piston seals allow metallic debris to circulate, often visible as dark, gritty fluid on the dipstick.
• Erratic shift timing: The piston’s inability to maintain steady pressure triggers unpredictable upshifts or downshifts, especially during highway cruising.

Technical Specifications

Compatibility

This piston is primarily designed for the ZF WG 150 series but also fits several other models in the WG family. Verified compatible transmissions include WG 150, WG 180, WG 200, and WG 210. It is also used in select off-highway and industrial drivelines where the WG 65 Series architecture is present. For proper sealing, always inspect the O-RING and SEALING RING during installation. Secure the assembly using HEXAGON SCREW fasteners to prevent fluid leaks.

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