ZF 4660.306.028 PISTON for WG 92/WG 98 | OEM Genuine Part

Overview

The ZF 4660.306.028 PISTON is a critical hydraulic actuation component engineered for the WG 92 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. The SKU 4660.306.028 sits directly inside the HOUSING assembly, where it must maintain a precise seal and smooth axial travel. When paired with the PERIPHERALS kit, this piston ensures consistent shift quality and prevents cross-port leakage in high-torque applications.

Symptoms of Failure

• Erratic gear engagement or delayed shifting: A worn 4660.306.028 piston allows hydraulic fluid to bypass the seal, causing soft or late clutch application during acceleration.
• Internal transmission oil leaks: Cracks or scoring on the piston face permit ATF to migrate into adjacent cavities, often visible as fluid accumulation near the TRANSMISSION HOUSING mating surfaces.
• Loss of low-range holding power: In WG 92/WG 200 units, a degraded piston cannot maintain clamping force, resulting in gear slip under load—especially during reverse or first-gear operation.
• Erratic shift patterns with the RANGE SELECTOR: When the piston fails to stroke fully, the range selector may produce grinding noises or fail to engage specific gear ratios.

Technical Specifications

Compatibility

This piston is specifically designed for the ZF WG 92 and WG 98 series transmissions, with verified fitment in the WG 200 Series category. It is also compatible with the following ZF models: WG180, WG200, WG210, and WG220. The 4660.306.028 replaces earlier revision pistons in WG 92/98 units where the SUCTION TUBE and O-RING assemblies are present. Always verify piston travel clearance when installing alongside the CAP SCREW and SCREW PLUG hardware.

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