ZF 4661.001.013 4 WG 90 Powershift Transmission Assembly | Complete Unit

Overview

The ZF 4661.001.013 4 WG 90 Powershift Transmission Assembly is a complete, factory-grade unit engineered for heavy-duty off-highway applications. This assembly serves as the central power distribution hub within the WG 90 series, managing torque flow and gear engagement across four forward and reverse speeds. The SKU 4661.001.013 integrates the main clutch pack, planetary gear sets, and hydraulic control valves into a single, ready-to-install package. When replacing this unit, it is critical to inspect the surrounding structural components, such as the TRANSMISSION HOUSING and the HOUSING II, for wear or damage that could compromise alignment.

Symptoms of Failure

• Delayed or harsh gear engagement: When the 4661.001.013 assembly wears, internal clutch packs slip, causing a noticeable lag or jolt when shifting from neutral to drive or reverse.
• Erratic hydraulic pressure fluctuations: A failing unit often leads to inconsistent oil pressure, resulting in surging or loss of power during operation under load.
• External oil seepage at the bell housing: Degraded seals within the assembly allow transmission fluid to leak past the main shaft, leaving puddles beneath the vehicle.
• Metallic grinding noises during shifts: Worn planetary gears or bearings produce a distinct grinding sound, especially when transitioning between forward and reverse ranges.

Technical Specifications

Compatibility

This complete unit is designed exclusively for the ZF WG 90 series powershift transmissions. It is a direct fit for models including the WG 90, WG 92, and WG 94. While the assembly is not interchangeable with the larger WG 180 or WG 200 series, it shares common mounting interfaces with the CYLINDRICAL PIN and the TUBE used across multiple WG variants. Always verify the serial number of your existing transmission before ordering to ensure correct spline count and valve body configuration.

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