ZF 4645.306.139 PISTON for WG100/WG201 | OEM Genuine Part

Overview

The ZF 4645.306.139 PISTON is a critical hydraulic actuation component engineered specifically for the WG100 and WG201 series transmissions. This OEM genuine part functions within the clutch pack assembly, converting hydraulic pressure into mechanical force to engage and disengage gear sets. The piston’s precise sealing surface and robust construction ensure consistent shift timing and torque transfer. When paired with a properly sealed TRANSMISSION HOUSING, this component maintains the internal pressure integrity required for smooth operation. The SKU 4645.306.139 is manufactured to ZF’s original tolerances, guaranteeing a direct fit without modification.

Symptoms of Failure

• Delayed or harsh gear engagement: A worn piston seal causes pressure loss, leading to sluggish shifts or abrupt clutch application.
• Internal transmission oil leaks: Cracks or scoring on the piston surface allow hydraulic fluid to bypass, often visible as oil pooling inside the bell housing.
• Gear slipping under load: Inability to hold pressure results in clutch pack slippage, particularly during acceleration or uphill driving.
• Erratic shift patterns: The transmission may hunt for gears or fail to hold a selected ratio due to inconsistent piston stroke.

Technical Specifications

Compatibility

This piston is designed for ZF WG-series transmissions, specifically the WG100 and WG201 models. It is also compatible with the WG180 and WG200 series when used in clutch pack positions requiring the same bore diameter. The part integrates directly with the TRANSMISSION HOUSING and requires a THREADED BUSH for secure alignment. For final sealing, a SCREW PLUG is recommended to prevent debris ingress. Always verify your transmission’s serial number against ZF’s parts catalog before ordering.

Related Components