ZF 4651.004.025 4 WG 100(500) Powershift Transmission Assembly | Complete Unit

Overview

The ZF 4651.004.025 4 WG 100(500) Powershift Transmission Assembly is a complete, factory-matched unit designed for heavy-duty off-highway applications. This assembly integrates the clutch pack, planetary gear sets, and hydraulic control components into a single, ready-to-install package. As the core power transfer module within the WG 100 series, it manages torque distribution across four forward speeds and one reverse range. The SKU 4651.004.025 is a direct replacement for original equipment assemblies, ensuring precise alignment with the TRANSMISSION HOUSING and the HOUSING that encloses the valve body. This unit eliminates the need for piecemeal rebuilding, reducing downtime in demanding environments like construction, mining, and material handling.

Symptoms of Failure

• Delayed or harsh engagement: When the assembly wears, you may notice a pronounced lag between shifting and actual gear engagement, often accompanied by a jarring clunk. This is a common sign of internal clutch pack degradation.
• Intermittent gear slipping under load: A failing unit will cause the transmission to momentarily lose torque during uphill climbs or heavy pulling, leading to RPM flare without corresponding vehicle speed increase.
• Contaminated or burnt transmission fluid: Friction material shedding from worn clutches turns the fluid dark and gives off a sharp burnt odor. This often coincides with debris clogging the SCREEN SHEET or the SCREEN SHEET in the sump.
• External oil seepage at mating flanges: Worn seals within the assembly can cause fluid to weep around the joint where the unit meets the HOUSING, often requiring a fresh O-RING to restore sealing integrity.

Technical Specifications

Compatibility

This complete assembly is engineered for the ZF WG 100 series of powershift transmissions. It is directly compatible with models including the WG 100, WG 100(500), and WG 100(600) variants commonly found in telehandlers, forklifts, and compact wheel loaders. While the unit shares mounting patterns with the WG 180 and WG 200 series, internal clutch ratios differ; always verify the SKU 4651.004.025 against your transmission’s serial plate. For installations requiring a new CAP SCREW or SEALING CAP, these are sold separately to ensure a leak-free fit.

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