Overview
The ZF 4644.026.295 6 WG 200(555/5) Powershift Transmission Assembly is a complete, factory-matched unit designed for heavy-duty off-highway machinery. This assembly integrates the main gear cluster, clutch packs, and hydraulic control elements into a single drop-in replacement. The SKU 4644.026.295 corresponds to the full WG 200 series assembly, which is the core power transfer module in articulated dump trucks, wheel loaders, and graders. When installed, this unit sits between the torque converter and the output driveline, managing all six forward speeds and one reverse gear. For proper sealing and structural integrity, this assembly mates directly with the 4644101220: TRANSMISSION HOUSING and the 4644301221: TRANSMISSION HOUSING to form the complete gearbox casing.
Symptoms of Failure
When the ZF 4644.026.295 assembly begins to degrade, operators will notice specific performance issues. Delayed or harsh engagement between gears is a primary indicator, often caused by worn clutch discs or degraded sealing rings within the unit. Intermittent loss of forward drive under load, particularly in higher gears, points to internal hydraulic pressure loss. Contaminated transmission fluid with metallic debris is a clear sign of bearing or gear tooth fatigue inside the assembly. Finally, audible whining or grinding noises from the transmission housing during shifts suggest that the planetary gear sets require immediate attention.
Technical Specifications
| Parameter | Specification |
|---|---|
| Part Number | 4644.026.295 |
| Assembly Type | Complete Powershift Transmission Unit |
| Series | WG 200 (6 WG 200) |
| Number of Speeds | 6 Forward / 1 Reverse |
| Dry Weight (approx.) | 385 kg (849 lbs) |
| Housing Material | High-Grade Cast Iron |
| OEM Reference | ZF 555/5 Variant |
| Input Torque Capacity | 2000 Nm (estimated) |
Compatibility
This complete assembly is engineered for the ZF WG 200 series, specifically the 6 WG 200(555/5) variant. It is also compatible with select WG 180 series transmissions that share the same bell housing pattern and input shaft spline count. The unit is commonly found in ZF 6WG200, 6WG180, and 4WG200 models used in construction equipment. For identification, ensure the 0730365067: TYPE PLATE on your existing transmission matches the 555/5 designation. During installation, the 0631311009: GROOVED STUD is required for precise alignment of the housing sections.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644101220 | TRANSMISSION HOUSING | Main casing for gear cluster |
| 4644301221 | TRANSMISSION HOUSING | Secondary housing section |
| 0730365067 | TYPE PLATE | Identification and specification tag |
| 0631311009 | GROOVED STUD | Alignment dowel for housing |
| 4644303060 | COVER PLATE | Access cover for valve body |
| 4644303061 | COVER PLATE | Alternate access cover |
| 0634306525 | O-RING | Hydraulic seal between sections |
| 0636305026 | SCREW PLUG | Drain or fill port plug |
| 4644301279 | SCREEN SHEET | Filter mesh for oil circuit |
| 4644301088 | SEALING CAP | Protective cap for ports |
