ZF 4651.004.008 4 WG 100(400) Powershift Transmission Assembly | Complete Unit

Overview

The ZF 4651.004.008 4 WG 100(400) Powershift Transmission Assembly is a complete, drop-in replacement unit engineered for heavy-duty off-highway vehicles. This fully assembled transmission integrates the torque converter, planetary gear sets, and hydraulic control system into a single, pre-tested package. As the core power transfer component, it sits directly between the engine flywheel and the driveline, managing gear ratio changes under load without interrupting power flow. The SKU 4651.004.008 is specifically calibrated for the WG 100 series, ensuring precise shift timing and clutch modulation. When paired with a robust TRANSMISSION HOUSING, this assembly provides the structural integrity needed for demanding applications like wheel loaders and graders.

Symptoms of Failure

• Erratic or delayed gear engagement: When the 4651.004.008 assembly wears, operators often experience a noticeable lag between shifting commands and actual gear changes, especially when moving from neutral to forward or reverse under load.
• Internal hydraulic pressure loss: Worn seals or clutch pack degradation within the unit can cause a gradual drop in system pressure, leading to “slipping” during acceleration or uphill travel. This is frequently accompanied by a whining noise from the pump section.
• External oil leaks at housing joints: Cracks or warpage in the main casing allow transmission fluid to escape, often pooling around the bell housing or output flange. Replacing the O-RING between the assembly and the mating housing is a common first step, but a complete unit replacement is required if the housing itself is compromised.
• Overheating during normal operation: A failing torque converter or blocked internal oil passages cause the transmission to run hotter than 220°F (104°C), triggering warning lights and reducing component life.

Technical Specifications

Compatibility

This complete unit is designed for the ZF WG 100 series, specifically the 4 WG 100(400) variant. It is directly compatible with ZF models WG 100, WG 101, and WG 102 used in compact wheel loaders, telehandlers, and backhoe loaders. While the WG 180 and WG 200 series share similar hydraulic architecture, they require different torque converter ratings and output flange configurations. For those larger series, inspect the HOUSING and HOUSING components to verify fitment. Always cross-reference your vehicle’s transmission serial number with the 4651.004.008 assembly before ordering.

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