Overview
The ZF 4661.004.051 4 WG 94 Powershift Transmission Assembly | Complete Unit is a fully integrated drop-in replacement designed for heavy-duty off-highway machinery. This complete assembly serves as the core power transfer module within the WG 94 series, managing clutch engagement and torque distribution across four forward and reverse speeds. The SKU 4661.004.051 identifies a factory-matched unit that includes the main gear cluster, valve body, and clutch packs. It mounts directly between the engine bellhousing and the final drive, with the 4661101028: TRANSMISSION HOUSING providing structural support and the 4661301049: HOUSING II enclosing the rear planetary set.
Symptoms of Failure
- Delayed or harsh engagement – When the complete unit wears, hydraulic pressure drops, causing a noticeable lag when shifting from neutral to drive or reverse.
- Internal oil leaks – Worn seals within the assembly allow transmission fluid to bypass, often pooling around the bellhousing or dripping from the vent tube.
- Gear slipping under load – A failing 4661.004.051 unit cannot maintain clutch pack clamping force, resulting in RPM flare without corresponding vehicle speed increase.
- Unusual whining or grinding noises – Bearing wear inside the complete assembly produces a high-pitched whine that intensifies with engine RPM, often accompanied by metallic debris in the oil pan.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 4661.004.051 |
| Assembly Type | Complete Powershift Transmission |
| Series | WG 94 |
| Dry Weight (approx.) | 185 kg (408 lbs) |
| Overall Length | 720 mm |
| Overall Width | 510 mm |
| Overall Height | 480 mm |
| Housing Material | High-Grade Cast Iron |
| OEM Reference | ZF 4661.004.051 |
| Oil Capacity | 22 Liters (approx.) |
Compatibility
This complete unit is engineered for the ZF WG 94 series of powershift transmissions. It is directly compatible with models including the WG180, WG200, and WG210 used in wheel loaders, graders, and telehandlers from manufacturers such as Volvo, JCB, and Caterpillar. The assembly also fits select WG 94 variants found in agricultural tractors and forestry skidders. Always verify the existing transmission model tag before installation; the 0769123894: TYPE PLATE provides the definitive model identifier. During installation, ensure the 4661301093: TUBE is correctly aligned for lubrication flow, and the 0631306174: CYLINDRICAL PIN is used to locate the housing halves precisely.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4661101028 | TRANSMISSION HOUSING | Main structural casing for gear train |
| 4661301049 | HOUSING II | Rear cover enclosing planetary gears |
| 4661301093 | TUBE | Lubrication oil delivery channel |
| 0631306174 | CYLINDRICAL PIN | Alignment dowel for housing assembly |
| 0769123894 | TYPE PLATE | Identification tag with model details |
| 0750100022 | SCREW PLUG | Seals oil drain or fill ports |
| 0636302602 | SCREW PLUG | Secondary port sealing plug |
| 0634100633 | O-RING | Hydraulic seal between components |
| 4661301029 | NOZZLE | Oil spray nozzle for clutch cooling |
| 4661301027 | NOZZLE | Secondary oil spray nozzle |
