ZF 5838.300.761 PISTON for WG100/WG130/WG131 | OEM Genuine Part

Overview

Within the intricate hydraulic control system of ZF’s WG-series powershift transmissions, the ZF 5838.300.761 PISTON serves as a critical actuation component. This OEM genuine part is responsible for converting hydraulic pressure into precise mechanical force, engaging clutch packs or brake bands to facilitate smooth gear changes under load. Designed specifically for the WG100, WG130, and WG131 models, this piston sits within the valve body or clutch housing assembly, ensuring that fluid power is reliably directed to the correct rotating elements. The SKU 5838.300.761 is a direct replacement for the factory-installed unit, guaranteeing the exact metallurgy and sealing geometry required for long service intervals in heavy-duty applications.

Symptoms of Failure

When the ZF 5838.300.761 PISTON begins to wear, operators often notice delayed or harsh gear engagement as the piston fails to move freely within its bore. A second common symptom is internal hydraulic pressure loss, leading to clutch slippage under load—particularly noticeable when climbing grades or hauling maximum payloads. You may also observe contaminated transmission fluid containing fine metallic particles, as the piston’s outer sealing surface degrades against the cylinder wall. Finally, erratic shifting patterns or a complete failure to shift into a specific gear range frequently point to a cracked or seized piston, which prevents proper oil flow to the clutch pack.

Technical Specifications

Compatibility

This piston is engineered for the ZF WG-series powershift transmissions, specifically the WG100, WG130, and WG131 models. It is also compatible with certain variants of the WG150 and WG180 series that share the same clutch piston bore dimensions. For applications in the WG200 or WG250, always verify the piston diameter and stroke length against your transmission’s service manual. The part integrates directly with the 2093109002 DIFFERENTIAL assembly and works in concert with the 0750117075 TAPER ROLLER BEARING to manage axial loads. Additionally, the piston’s housing mates with the 2093309071 DIFF.HOUSING and the 2093209095 DIFFERENTIAL unit in the final drive section.

Related Components

Frequently Asked Questions

Q: Can I install the ZF 5838.300.761 PISTON without removing the transmission from the vehicle?
A: In most WG100/WG130 applications, the piston is accessible after removing the valve body cover. However, due to tight clearances, we recommend a partial transmission drop to avoid damaging the sealing ring during installation.

Q: What is the typical service life of this piston before replacement is needed?
A: Under normal operating conditions with clean fluid, the piston can last 8,000–10,000 hours. Early replacement is advised if you notice any of the failure symptoms listed above, as a seized piston can damage the clutch housing bore.

Q: Does this part include the return spring or seals?
A: No, the 5838.300.761 is supplied as the bare piston only. You will need to order the corresponding seal kit and spring separately. We recommend replacing the 0730300820 THRUST WASHER at the same time to ensure proper clearance.