Overview
The ZF 4644.026.392 6 WG 200(555/5) Powershift Transmission Assembly | Complete Unit is a fully assembled, ready-to-install powershift transmission designed for heavy-duty industrial and agricultural machinery. This complete unit integrates the gearbox, clutch packs, and hydraulic control system into a single, robust assembly, serving as the primary power transfer module in ZF’s WG 200 series. The SKU 4644.026.392 specifically denotes a 6-speed forward, 1-reverse configuration with a 555/5 ratio set, optimized for high-torque applications. It sits centrally within the drivetrain, connecting the engine to the final drive, and is engineered for seamless integration with supporting components such as the 4644101249: TRANSMISSION HOUSING and the 4644301402: TRANSMISSION HOUSING, which provide structural integrity and oil containment.
Symptoms of Failure
When the ZF 4644.026.392 assembly begins to degrade, operators often notice distinct performance issues. Common failure symptoms include:
- Erratic gear engagement or slipping – The transmission may hesitate or fail to hold a gear under load, often due to worn clutch discs or degraded seals within the unit.
- Hydraulic oil leaks – Visible fluid seepage around the housing joints or output shafts, frequently caused by a compromised 0634306323: O-RING or damaged sealing surfaces.
- Delayed or harsh shifting – A noticeable lag or jarring sensation when changing speeds, indicating internal pressure loss or valve body wear.
- Unusual whining or grinding noises – Audible sounds from the transmission casing, often signaling bearing fatigue or gear tooth damage inside the complete unit.
Technical Specifications
| Specification | Detail |
|---|---|
| Part Number | 4644.026.392 |
| Transmission Type | Powershift, 6 WG 200 (555/5) |
| Gear Configuration | 6 Forward / 1 Reverse |
| Housing Material | High-strength cast iron |
| Dry Weight (approx.) | 285 kg (628 lbs) |
| OEM Reference | ZF 4644.026.392 |
| Max Input Torque | 555 Nm (estimated) |
| Fluid Capacity | 12.5 liters (approx.) |
Compatibility
This complete unit is primarily designed for the ZF WG 200 Series transmissions, including models such as the WG180, WG200, and WG210. It is a direct fit for machinery requiring a 6-speed powershift with a 555/5 ratio, commonly found in telehandlers, wheel loaders, and agricultural tractors. For proper assembly, ensure the 4644301298: COVER PLATE is installed to seal the upper housing, and verify that all mating surfaces are clean to prevent contamination.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644101249 | TRANSMISSION HOUSING | Main structural casing for gear and shaft support |
| 4644301402 | TRANSMISSION HOUSING | Secondary housing for oil sump and clutch pack |
| 4644301298 | COVER PLATE | Seals the upper transmission access point |
| 0634306323 | O-RING | Prevents fluid leaks at housing joints |
| 0636305026 | SCREW PLUG | Seals drain and fill ports |
| 4644301279 | SCREEN SHEET | Filters debris from hydraulic fluid |
| 4644301088 | SEALING CAP | Protects exposed shaft ends |
| 4644109046 | PARKING BRAKE | Engages parking lock mechanism |
| 0501216078 | BRAKE | Service brake for wheel-end stopping |
| 0501298641 | SEAL KIT | Contains all gaskets and O-rings for rebuild |
