ZF 4651.364.023 PISTON for WG 100/WG 110 | OEM Genuine Part

Overview

The ZF 4651.364.023 PISTON is a critical hydraulic actuation component engineered specifically for the WG 100 and WG 110 transmission series. This OEM genuine part functions as a pressure-driven actuator within the valve body assembly, converting hydraulic force into mechanical motion to engage clutch packs and shift gears. The piston’s precise sealing surface ensures consistent oil pressure delivery, directly influencing shift quality and torque transmission. Identified by SKU 4651.364.023, this component sits adjacent to the 4651101006: TRANSMISSION HOUSING and works in concert with the 4651301034: HOUSING to maintain internal fluid dynamics. When this piston degrades, the entire hydraulic circuit loses integrity, leading to performance degradation across the gear range.

Symptoms of Failure

• Delayed or harsh gear engagement: A worn 4651.364.023 piston allows internal pressure bleed, causing noticeable lag when shifting from Neutral to Drive or Reverse, often accompanied by a jarring thud.
• Intermittent gear slippage under load: As the piston loses its seal, the clutch pack fails to hold torque, resulting in RPM flare without corresponding acceleration, particularly during uphill driving or heavy hauling.
• Hydraulic fluid contamination: Cracking or scoring on the piston surface introduces metal debris into the transmission fluid, visible as dark particles on the dipstick or during a fluid change.
• Erratic shift patterns: The transmission may hunt between gears or skip shifts entirely due to inconsistent hydraulic pressure regulation caused by a failing piston.

Technical Specifications

Compatibility

This piston is factory-specified for the ZF WG 100 and WG 110 series transmissions, commonly found in medium-duty commercial vehicles, municipal trucks, and off-highway equipment. While the WG 100 and WG 110 are the primary applications, the 4651.364.023 may also be compatible with the WG 180 and WG 200 series where identical hydraulic piston dimensions are used in auxiliary pressure circuits. Always verify piston bore diameter and stroke length against your transmission’s service manual. The piston interfaces directly with the 4651301013: HOUSING and requires a fresh 0634303928: O-RING during installation to prevent cross-port leakage.

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