Overview
The ZF 4661.002.009 4 WG 90 Powershift Transmission Assembly is a complete, factory-grade unit designed for heavy-duty off-highway machinery. This assembly serves as the central torque-converter and gearbox module within the WG 90 series, managing power distribution from the engine to the drivetrain under high-stress conditions. The SKU 4661.002.009 integrates the planetary gear sets, clutch packs, and hydraulic valve body into a single sealed assembly, ensuring precise shift modulation for wheel loaders, graders, and industrial tractors. When replacing this unit, it is critical to inspect the surrounding TRANSMISSION HOUSING for cracks or wear, as the assembly seats directly into this structural component.
Symptoms of Failure
- Delayed or harsh gear engagement: When the 4661.002.009 assembly loses hydraulic pressure, operators experience a 2-3 second lag between shifting and actual gear change, often accompanied by a clunking noise.
- Torque converter shudder under load: A rhythmic vibration during low-speed, high-torque operations indicates worn clutch discs or damaged stator bearings within the unit.
- External oil seepage from the bell housing: Leaks typically originate from failed seals between the assembly and the CYLINDRICAL PIN alignment points, leaving puddles of ATF under the machine.
- Overheating transmission fluid: A sudden rise in sump temperature above 120°C (248°F) suggests internal friction from failing thrust washers or blocked oil passages inside the 4661.002.009.
Technical Specifications
| Parameter | Value |
|---|---|
| OEM Part Number | 4661.002.009 |
| Assembly Type | 4 WG 90 Powershift (Complete Unit) |
| Dry Weight | Approx. 185 kg (408 lbs) |
| Overall Length | 620 mm |
| Housing Material | High-tensile cast iron (GGG-40) |
| Max Input Torque | 1,200 Nm |
| Oil Capacity | 12.5 liters (ZF TE-ML 03 fluid) |
| Bolt Torque (housing) | 85 Nm (M12 bolts) |
| Related Seal Kit | O-RING (0634100633) |
| Identification | TYPE PLATE (0769123894) |
Compatibility
This complete unit is engineered for the ZF WG 90 series, specifically the 4 WG 90 variant. It is directly compatible with the following ZF transmission models: WG 90, WG 180 (with adapter plate), WG 200 (early series), and WG 120. The assembly also fits select ZF 4WG-90 and ZF 4WG-180 off-highway applications. During installation, ensure the HOUSING II (4661301047) is free of debris, and verify the TUBE (4661301093) is properly aligned to prevent oil starvation to the rear clutch pack.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4661101021 | TRANSMISSION HOUSING | Main structural casing for gear train |
| 4661301047 | HOUSING II | Rear section housing output shaft |
| 4661301093 | TUBE | Oil supply tube for clutch lubrication |
| 0631306174 | CYLINDRICAL PIN | Alignment dowel for housing mating |
| 0769123894 | TYPE PLATE | Identification tag with serial number |
| 0750100022 | SCREW PLUG | Magnetic drain plug for sump |
| 0636302602 | SCREW PLUG | Hex plug for pressure test port |
| 0634100633 | O-RING | Seal for plug and housing interfaces |
| 4661301041 | NOZZLE | Oil spray nozzle for gear cooling |
| 4661301062 | NOZZLE | Secondary oil nozzle for planetary set |
