Overview
The ZF 4644.026.291 6 WG 200(555/5) Powershift Transmission Assembly is a complete, factory-matched unit designed for heavy-duty off-highway applications. This assembly integrates the main gear cluster, clutch packs, and hydraulic control components into a single, ready-to-install package. As the core power transfer module within the WG 200 Series, it replaces the entire rotating and shifting assembly, eliminating the need for piecemeal repairs. The SKU 4644.026.291 is the direct OEM reference for this complete unit, ensuring precise fitment and performance. When installing this assembly, it is critical to pair it with a properly sealed 4644101180: TRANSMISSION HOUSING to maintain structural integrity and fluid containment.
Symptoms of Failure
- Erratic gear engagement and clutch chatter: When the internal clutch packs or sprag clutches wear, operators experience harsh, delayed, or slipping shifts under load, particularly in forward/reverse direction changes.
- Low hydraulic pressure and overheating: Internal seal failures within the assembly cause pressure drops, leading to transmission overheating (above 120°C) and sluggish response in all gears.
- Metallic debris in the oil filter or pan: Worn bearings or gear teeth produce fine metal particles, which can be detected during routine oil changes and indicate imminent internal failure.
- Complete loss of drive in one or more ranges: A fractured sun gear or failed clutch piston results in a no-drive condition in specific gear ranges, often accompanied by unusual whining or grinding noises.
Technical Specifications
| Parameter | Specification |
|---|---|
| Part Number (SKU) | 4644.026.291 |
| Assembly Type | Complete Powershift Unit (6 WG 200/555/5) |
| Weight (estimated) | 185 kg (408 lbs) |
| Housing Material | High-strength cast iron (GGG-40) |
| Overall Length | 620 mm |
| Overall Width | 480 mm |
| Overall Height | 510 mm |
| OEM Reference | ZF 4644.026.291 |
| Torque Capacity | Up to 555 Nm (409 lb-ft) |
| Gear Count | 6 forward / 1 reverse |
Compatibility
This complete assembly is engineered for the ZF WG 200 Series, specifically the 6 WG 200(555/5) variant. It is directly compatible with WG 180 and WG 200 transmissions used in telehandlers, wheel loaders, and agricultural tractors from manufacturers such as JCB, Manitou, and Claas. The unit also fits select WG 150 models with adapter modifications. For proper installation, always verify the housing condition; a damaged 4644301225: TRANSMISSION HOUSING must be replaced to prevent misalignment. Additionally, ensure the 0730365067: TYPE PLATE is present for correct identification, and secure the assembly using the 0631311009: GROOVED STUD for precise torque retention.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644101180 | TRANSMISSION HOUSING | Main structural casing for the assembly |
| 4644301225 | TRANSMISSION HOUSING | Alternate housing variant for WG 200 |
| 0730365067 | TYPE PLATE | Identification plate for model verification |
| 0631311009 | GROOVED STUD | Fastener for housing-to-assembly mounting |
| 4644301298 | COVER PLATE | Seals the access port on the housing |
| 0634306525 | O-RING | Hydraulic seal for fluid circuits |
| 0636305026 | SCREW PLUG | Drain/fill port closure |
| 4644301279 | SCREEN SHEET | Filter mesh for oil debris |
| 4644301088 | SEALING CAP | Protects exposed hydraulic ports |
| 4644106300 | SHIFT SYSTEM | Electro-hydraulic control module |
