Overview
The ZF 4644.026.394 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 a core element of the WG 200 Series, it manages torque distribution across six forward and three reverse speeds, ensuring smooth power delivery under extreme loads. The SKU 4644.026.394 is a direct OEM replacement, eliminating the need for piecemeal repairs. When rebuilding this assembly, always inspect the TRANSMISSION HOUSING (4644101249) and the TRANSMISSION HOUSING (4644301402) for cracks or warping, as these housings form the structural backbone of the unit.
Symptoms of Failure
- Delayed or harsh engagement: When the powershift assembly wears, hydraulic pressure drops, causing a noticeable lag or clunk when shifting between forward and reverse. This often points to internal seal degradation within the 4644.026.394 unit.
- Torque converter shudder under load: A vibration or shudder during acceleration, especially on inclines, indicates worn clutch discs or a failing stator. This symptom is common in high-hour WG 200 transmissions.
- External oil seepage at the bell housing: Leaks originating from the joint between the transmission and engine often trace back to a compromised O-RING (0634306323) or a damaged COVER PLATE (4644301298). Left unchecked, fluid loss accelerates internal wear.
- Erratic shift patterns or gear slippage: If the transmission unexpectedly drops out of gear or hunts between ratios, the powershift assembly’s valve body or piston seals are likely failing. This requires immediate attention to prevent secondary damage.
Technical Specifications
| Parameter | Specification |
|---|---|
| Part Number | 4644.026.394 |
| Assembly Type | Complete Powershift Unit (6 WG 200) |
| Weight (estimated) | 185 kg (408 lbs) |
| Housing Material | High-strength cast iron |
| OEM Reference | ZF 6 WG 200(555/5) |
| Max Input Torque | 555 Nm (409 lb-ft) |
| Gear Count | 6 Forward / 3 Reverse |
| Seal Kit Compatible | 0501298641: SEAL KIT |
| Brake Interface | 0501216078: BRAKE |
Compatibility
This assembly is engineered for the ZF WG 200 Series, specifically the 6 WG 200(555/5) variant. It is also compatible with the WG 180 and WG 210 models when used with the correct adapter plates. The 4644.026.394 unit fits telehandlers, wheel loaders, and industrial tractors from manufacturers like Manitou, JCB, and Claas. For parking brake integration, use the PARKING BRAKE (4644109046) assembly. Always verify the bell housing pattern against your existing SCREEN SHEET (4644301279) and SEALING CAP (4644301088) to ensure proper fitment.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644101249 | TRANSMISSION HOUSING | Main structural casing for gear train |
| 4644301402 | TRANSMISSION HOUSING | Secondary housing for clutch pack |
| 4644301298 | COVER PLATE | Seals the valve body cavity |
| 0634306323 | O-RING | Hydraulic seal between housings |
| 0636305026 | SCREW PLUG | Oil drain/fill port seal |
| 4644301279 | SCREEN SHEET | Filter mesh for hydraulic fluid |
| 4644301088 | SEALING CAP | Protects sensor ports from debris |
| 4644109046 | PARKING BRAKE | Spring-applied, hydraulic-release brake |
| 0501216078 | BRAKE | Service brake disc assembly |
| 0501298641 | SEAL KIT | Complete o-ring and gasket set |
