Overview
The ZF 4644.026.331 6 WG 200 Powershift Transmission Assembly is a complete, factory-grade unit designed for heavy-duty off-highway machinery. This assembly integrates the main gear train, clutch packs, and hydraulic control circuits into a single, ready-to-install package. As the core of the WG 200 series, it manages torque distribution across six forward speeds, ensuring smooth power delivery under extreme loads. The SKU 4644.026.331 identifies this as a fully assembled unit, replacing worn or failed transmissions in wheel loaders, graders, and dump trucks. It sits directly between the engine flywheel housing and the final drive, with the TRANSMISSION HOUSING (part 4644101232) and the TRANSMISSION HOUSING (part 4644301282) providing structural support for the internal shafts and bearings.
Symptoms of Failure
- Erratic gear engagement or slipping under load: Worn clutch discs or degraded seals inside the assembly cause delayed shifts or loss of torque, especially when climbing grades.
- External oil leaks near the housing joints: Cracks in the casing or failed gaskets allow hydraulic fluid to escape, often visible as drips around the bell housing. A faulty O-RING (part 0634306198) is a common culprit.
- Unusual whining or grinding noises during operation: Bearing wear or gear tooth damage inside the unit produces metallic sounds that intensify with speed changes.
- Overheating transmission fluid: Internal friction from worn components generates excess heat, triggering warning lights or fluid discoloration.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 4644.026.331 |
| Assembly Type | Complete Powershift Unit (6 WG 200) |
| Overall Length | ~720 mm |
| Dry Weight | ~185 kg (408 lbs) |
| Housing Material | High-Grade Cast Iron |
| OEM Reference | ZF 6 WG 200 |
| Max Input Torque | 2,000 Nm |
| Fluid Capacity | ~12 Liters |
Compatibility
This assembly is engineered for the ZF WG 200 series of powershift transmissions. It is directly compatible with the WG180, WG200, and WG210 models used in construction and agricultural vehicles. The unit also fits select variants of the WG150 when paired with the correct SCREW PLUG (part 4475280043) for port sealing. Always verify the bell housing pattern and output flange configuration against your original transmission tag, such as the TYPE PLATE (part 0730365067).
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644101232 | TRANSMISSION HOUSING | Encloses the gear train and supports shafts |
| 4644301282 | TRANSMISSION HOUSING | Rear housing section for output shaft |
| 4475280043 | SCREW PLUG | Seals hydraulic ports and drain holes |
| 0634306198 | O-RING | Prevents fluid leaks at housing joints |
| 0730365067 | TYPE PLATE | Identification tag with model and serial |
| 4644301298 | COVER PLATE | Protects internal components from debris |
| 4644106300 | SHIFT SYSTEM | Controls clutch engagement for gear changes |
| 4644306500 | COVER PLATE | Access cover for valve block maintenance |
| 4644159300 | SHIFT SYSTEM | Secondary shift actuator for reverse gears |
| 4644306560 | VALVE BLOCK | Regulates hydraulic pressure to clutches |
