Overview
The ZF 4644.026.333 6 WG 200(555/5) Powershift Transmission Assembly is a complete, factory-matched unit designed for heavy-duty off-highway applications. This SKU 4644.026.333 integrates the clutch packs, planetary gearsets, and hydraulic control system into a single drop-in assembly, serving as the core power transfer module within the WG 200 series. It replaces the need for individual component rebuilding, ensuring precise gear engagement under high torque loads. The assembly interfaces directly with the 4644101249: TRANSMISSION HOUSING and the 4644301402: TRANSMISSION HOUSING to form the main structural enclosure, while the 4644301298: COVER PLATE seals the valve body cavity. A critical sealing element, the 0634306323: O-RING, is used at the main housing interface to prevent fluid migration.
Symptoms of Failure
- Erratic or delayed shifting under load: When the internal clutch packs or sprag clutches wear, the transmission may hesitate or slam into gear, particularly when transitioning from forward to reverse. This is a common long-tail search query for “ZF WG200 shifting delay.”
- Low hydraulic pressure and overheating: Worn seals or scored valve bores within the assembly cause internal leakage, leading to a drop in line pressure. Operators often notice transmission fluid temperatures exceeding 120°C (248°F) during normal operation.
- Metallic debris in the oil pan: As friction material or planetary gear teeth degrade, fine metallic particles contaminate the hydraulic fluid. This debris can clog the 4644301279: SCREEN SHEET, accelerating wear across the entire system.
- Inability to hold position on a grade: A failing powershift unit may allow the vehicle to creep forward or backward when the transmission is in gear and the engine is at idle, indicating internal clutch slippage.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number / SKU | 4644.026.333 |
| Assembly Type | Complete Powershift Unit (6 WG 200) |
| OEM Reference | ZF 6 WG 200(555/5) |
| Dry Weight (approx.) | 185 kg (408 lbs) |
| Overall Length | 720 mm |
| Overall Width | 480 mm |
| Overall Height | 410 mm |
| Housing Material | High-strength cast iron (GGG-40) |
| Max Input Torque | 555 Nm (409 lb-ft) |
| Number of Speeds | 6 forward / 1 reverse |
| Hydraulic Fluid Capacity | 12.5 liters (integrated) |
| Sealing System | Integrated O-ring & gasket set |
Compatibility
This assembly is specifically engineered for the ZF WG 200 series powershift transmissions. It is a direct fit for models including the 6 WG 200, 6 WG 180, and 6 WG 160, provided they utilize the 555/5 gear ratio configuration. The unit is commonly found in telescopic handlers, wheel loaders, and rough-terrain forklifts from manufacturers such as Manitou, JCB, and Merlo. Always verify the transmission serial number against the SKU 4644.026.333 to confirm compatibility. For parking functions, the 4644109044: PARKING BRAKE and 0501211070: BRAKE assemblies mount externally, while the 0501317036: PISTON actuates the clutch packs internally.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644101249 | TRANSMISSION HOUSING | Main structural casing for gear train |
| 4644301402 | TRANSMISSION HOUSING | Secondary housing for clutch pack section |
| 4644301298 | COVER PLATE | Seals valve body and hydraulic passages |
| 0634306323 | O-RING | Fluid seal between housing sections |
| 0636305026 | SCREW PLUG | Seals oil drain/fill ports |
| 4644301279 | SCREEN SHEET | Filters debris from hydraulic fluid |
| 4644301088 | SEALING CAP | Protects pressure test ports |
| 4644109044 | PARKING BRAKE | Spring-applied, hydraulically released brake |
| 0501211070 | BRAKE | Service brake disc assembly |
| 0501317036 | PISTON | Hydraulic actuator for clutch engagement |
