Overview
The ZF 4661.004.018 4 WG 94 Powershift Transmission Assembly is a complete, factory-grade unit designed for heavy-duty off-highway applications. This assembly serves as the core power distribution hub within the WG 94 series, managing torque flow from the engine to the drivetrain through four forward and multiple reverse clutch packs. The SKU 4661.004.018 integrates the main valve body, planetary gear sets, and output shaft housing into a single, ready-to-install package. When replacing this unit, it is critical to inspect the 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 4661.004.018 assembly wears, internal clutch piston seals degrade, causing a 2-3 second lag when shifting from neutral to forward or reverse.
- Low hydraulic pressure and overheating: Worn valve body bores within the unit lead to pressure drops below 180 psi, triggering transmission over-temperature warnings on the dash.
- Torque converter shudder under load: A failing stator support inside the assembly produces a distinct vibration at 1200-1500 RPM during grading or dozing operations.
- External oil seepage at the bell housing: Cracks in the assembly’s rear cover allow ATF to pool around the CYLINDRICAL PIN mounting points, often mistaken for a simple gasket leak.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number / SKU | 4661.004.018 |
| Assembly Type | 4 WG 94 Powershift (Complete Unit) |
| Dry Weight | ~185 kg (408 lbs) |
| Overall Length | 720 mm |
| Overall Width | 480 mm |
| Overall Height | 410 mm |
| Housing Material | High-grade cast iron (GGG-40) |
| OEM Reference | ZF 4661.004.018 / 4 WG-94 |
| Max Input Torque | 1,200 Nm |
| Max Input Speed | 2,800 RPM |
| Hydraulic Pressure Range | 180-220 psi (12.4-15.2 bar) |
| Oil Capacity (system) | 22 liters |
Compatibility
This 4 WG 94 assembly is engineered for the ZF WG series powershift transmissions, specifically the WG94, WG120, and WG150 models used in telescopic handlers, wheel loaders, and backhoe loaders. It also retrofits into select WG180 and WG200 configurations when paired with the correct HOUSING II adapter plate. For proper oil circulation, ensure the TUBE (part 4661301093) is replaced simultaneously to avoid debris contamination from the old assembly.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4661101023 | TRANSMISSION HOUSING | Main structural casing that encloses the gear train |
| 4661301051 | HOUSING II | Intermediate housing for clutch pack alignment |
| 4661301093 | TUBE | Oil delivery tube for lubrication circuits |
| 0631306174 | CYLINDRICAL PIN | Alignment dowel for housing-to-assembly fitment |
| 0769123894 | TYPE PLATE | Identification tag with serial number |
| 0750100022 | SCREW PLUG | Seals hydraulic test ports |
| 0636302602 | SCREW PLUG | Magnetic drain plug for debris collection |
| 0634100633 | O-RING | Seals the tube-to-housing connection |
| 4661301029 | NOZZLE | Sprays oil onto reverse clutch pack |
| 4661301027 | NOZZLE | Sprays oil onto forward clutch pack |
