Overview
The ZF 4644.026.332 6 WG 200(555/5) Powershift Transmission Assembly | Complete Unit is a fully assembled, drop-in replacement for heavy-duty powershift transmissions in the WG 200 series. This complete unit integrates the main gear cluster, clutch packs, and hydraulic control system into a single, pre-tested assembly. The SKU 4644.026.332 designates a specific build configuration for the 6-speed WG 200, ensuring precise fitment and OEM-level performance. It sits as the core driveline component, transferring engine torque through the transmission housing and output shaft. For a full rebuild, always inspect the 4644101249: TRANSMISSION HOUSING and the 4644301402: TRANSMISSION HOUSING for cracks or wear, as these housings directly support the complete unit.
Symptoms of Failure
When the ZF 4644.026.332 assembly begins to fail, operators typically notice these specific issues:
- Delayed or harsh gear engagement – The transmission hesitates before engaging forward or reverse, often accompanied by a clunking noise. This indicates worn clutch packs or hydraulic pressure loss inside the unit.
- Internal oil leaks pooling under the bell housing – Seals and gaskets degrade, causing transmission fluid to escape. Check the 0634306323: O-RING and the 4644301298: COVER PLATE for proper sealing during installation.
- Gear slipping under load – The engine revs higher than expected without proportional vehicle speed increase, especially on inclines. This points to failing clutches or a damaged torque converter within the assembly.
- Unusual whining or grinding noises – Metallic sounds from the transmission case suggest bearing failure or gear tooth damage, requiring immediate replacement of the complete unit.
Technical Specifications
| Parameter | Specification |
|---|---|
| Part Number | 4644.026.332 |
| Series | WG 200 (6 WG 200) |
| Gear Ratio | 555/5 (specific ratio configuration) |
| Weight (approx.) | 185 kg (408 lbs) |
| Housing Material | Cast iron / aluminum alloy |
| OEM Reference | ZF 4644.026.332 |
| Seal Type | O-ring and gasket sealed |
Compatibility
This complete unit is engineered for the ZF WG 200 series powershift transmissions, specifically the 6 WG 200 variant with the 555/5 ratio. It is also compatible with the WG 180 and WG 200 families when used with the correct adapter housings. The assembly fits industrial vehicles such as loaders, graders, and heavy-duty trucks. Always verify the transmission serial number against the SKU 4644.026.332 before ordering. For supporting components, consider the 0636305026: SCREW PLUG for drain ports and the 4644301279: SCREEN SHEET for filtration.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644101249 | TRANSMISSION HOUSING | Main structural casing for gear train |
| 4644301402 | TRANSMISSION HOUSING | Secondary housing for clutch packs |
| 4644301298 | COVER PLATE | Seals the transmission access port |
| 0634306323 | O-RING | Fluid seal between housing sections |
| 0636305026 | SCREW PLUG | Closes oil drain/fill holes |
| 4644301279 | SCREEN SHEET | Filters debris from hydraulic fluid |
| 4644301088 | SEALING CAP | Protects exposed ports during storage |
| 4644109044 | PARKING BRAKE | Engages parking lock mechanism |
| 0501211070 | BRAKE | Service brake for output shaft |
| 0501317036 | PISTON | Hydraulic actuator for clutch/brake |
