Overview
The ZF 4661.002.013 4 WG 90 Powershift Transmission Assembly is a complete, factory-matched unit designed for heavy-duty off-highway applications. This fully assembled gearbox integrates the torque converter, clutch packs, and final drive into a single, ready-to-install package. As a core component of the WG 90 Series, the SKU 4661.002.013 replaces the entire transmission assembly, eliminating the need for piecemeal repairs. It sits as the primary power transfer unit between the engine and the driveline, managing all gear ratio changes under load. When installing this assembly, it is critical to inspect the TRANSMISSION HOUSING for cracks and the HOUSING II for wear at the bearing seats to ensure a leak-free seal.
Symptoms of Failure
When the complete ZF 4661.002.013 assembly begins to degrade, operators will notice distinct performance issues. Recognizing these symptoms early can prevent catastrophic driveline damage.
- Erratic shifting under load: The transmission may hesitate, slam into gear, or fail to hold a ratio when climbing grades. This often points to internal clutch pack wear within the assembly.
- Torque converter shudder: A low-frequency vibration during acceleration from a stop indicates failing stator or turbine components inside the unit.
- External fluid seepage at the bell housing: Oil leaks around the input shaft or the joint between the TRANSMISSION HOUSING and the main case suggest seal failure, requiring immediate attention.
- Loss of forward or reverse drive: If the vehicle moves sluggishly in one direction but not the other, the directional clutch pack within the 4661.002.013 has likely failed.
Technical Specifications
| Parameter | Specification |
|---|---|
| OEM Part Number | 4661.002.013 |
| Assembly Type | 4 WG 90 Powershift (Complete Unit) |
| Dry Weight (Approx.) | 385 kg (849 lbs) |
| Overall Length | 720 mm |
| Housing Material | High-Grade Cast Iron (GGG-40) |
| Torque Converter Diameter | 390 mm |
| Number of Speeds | 4 Forward / 4 Reverse |
| Max Input Torque | 900 Nm |
| Fluid Capacity | 22 Liters (ATF Dexron III) |
| OEM Reference | ZF 4 WG 90 |
Compatibility
This complete unit is specifically engineered for the ZF WG 90 series powershift transmissions. It is a direct replacement for models including the WG90, WG92, and WG94 found in telescopic handlers, wheel loaders, and industrial tractors. While the 4661.002.013 is a complete assembly, it requires the use of the RANGE SELECTOR to control gear engagement. Additionally, the PERIPHERALS kit (including filters and seals) must be replaced concurrently to maintain hydraulic pressure integrity. This unit does not fit the WG180 or WG200 series without significant adapter modifications.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4661198001 | PERIPHERALS | Filter and seal kit for hydraulic circuit |
| 0501216064 | RANGE SELECTOR | Manual shift control valve assembly |
| 4661101032 | TRANSMISSION HOUSING | Main structural case for gear cluster |
| 4661301047 | HOUSING II | Rear cover housing for output shaft |
| 4661301093 | TUBE | Oil delivery tube for clutch lubrication |
| 0631306174 | CYLINDRICAL PIN | Alignment dowel for housing mating |
| 0769123894 | TYPE PLATE | Identification plate with serial number |
| 0750100022 | SCREW PLUG | Magnetic drain plug for oil pan |
| 0636302602 | SCREW PLUG | Hex socket plug for pressure test port |
| 0634100633 | O-RING | Seal for housing joint surfaces |
