Overview
The ZF 4661.001.004 4 WG 90 Powershift Transmission Assembly | Complete Unit is a fully assembled, drop-in replacement for heavy-duty powershift applications. This complete unit integrates the main gear cluster, clutch packs, and hydraulic control system into a single, pre-tested assembly. As the core of the WG 90 series, it manages torque distribution across four forward and reverse speeds. The SKU 4661.001.004 identifies this as the complete unit, ensuring direct compatibility with existing drivelines. It works in concert with the 4661101020: TRANSMISSION HOUSING to provide structural integrity and with the 4661301046: HOUSING II to enclose the rear planetary sets.
Symptoms of Failure
- Delayed or harsh engagement: When the complete unit wears, hydraulic pressure drops, causing a noticeable lag or jarring shift between forward and reverse.
- Oil leaks near the bell housing: Worn seals within the assembly allow transmission fluid to escape, often pooling under the vehicle after extended operation.
- Gear slipping under load: Internal clutch pack wear leads to power loss during acceleration or when climbing grades, with the engine revving without proportional movement.
- Unusual whining or grinding noises: Bearing fatigue inside the unit produces a high-pitched whine that intensifies with speed, indicating imminent failure.
Technical Specifications
| Parameter | Value |
|---|---|
| Product Type | Complete Powershift Transmission Assembly |
| OEM Reference | ZF 4661.001.004 |
| Weight (approx.) | 185 kg (408 lbs) |
| Dimensions (L x W x H) | 620 mm x 480 mm x 510 mm |
| Housing Material | High-grade cast iron with aluminum clutch covers |
| Number of Speeds | 4 Forward / 4 Reverse (powershift) |
| Torque Capacity | Up to 900 Nm (estimated for WG 90 series) |
| Fluid Capacity | Approx. 12 liters (ZF TE-ML 03 spec) |
Compatibility
This complete unit is engineered for the ZF WG 90 series of powershift transmissions. It is a direct fit for models including the WG 90, WG 100, and WG 120, commonly found in wheel loaders, telehandlers, and industrial tractors. The assembly also supports the WG 150 and WG 180 variants when paired with the correct 4661301093: TUBE for oil routing. For precise alignment during installation, the 0631306174: CYLINDRICAL PIN is required to locate the unit within the chassis.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4661101020 | TRANSMISSION HOUSING | Main structural casing for gear train |
| 4661301046 | HOUSING II | Rear cover for planetary gear sets |
| 4661301093 | TUBE | Oil supply conduit between sections |
| 0631306174 | CYLINDRICAL PIN | Alignment dowel for assembly |
| 0769123894 | TYPE PLATE | Identification label for unit |
| 0750100022 | SCREW PLUG | Seals fluid drain port |
| 0636302602 | SCREW PLUG | Seals pressure test port |
| 0634100633 | O-RING | Hydraulic seal for plug |
| 4661301041 | NOZZLE | Lubrication jet for gears |
| 4661301038 | NOZZLE | Coolant spray nozzle for clutches |
