Overview
The ZF 4644.026.365 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 system into a single ready-to-install package. As the core rotating assembly within the WG 200 series, it transfers engine torque through six forward speeds and one reverse, with a power-to-weight ratio optimized for loaders, graders, and material handlers. The SKU 4644.026.365 replaces worn or damaged internal rotating groups, restoring full shift quality and driveline efficiency without requiring individual gear or bearing replacement.
Symptoms of Failure
- Erratic or delayed shifting under load: When the 4644.026.365 assembly wears, hydraulic pressure losses cause hesitation between gears, especially during directional changes. Operators report a “slip” sensation before engagement.
- Metallic grinding noise from the bell housing: Worn clutch discs or bearing surfaces within the assembly produce a distinct high-pitched whine or grinding sound that intensifies with engine RPM.
- Transmission overheating with low oil pressure: Internal leakage past worn seals in the 4644.026.365 reduces pump efficiency, leading to elevated sump temperatures and warning lamp activation.
- Inability to hold position on inclines: A failing assembly allows the output shaft to creep when the transmission is in gear, indicating worn sprag clutches or planetary gear damage.
Technical Specifications
| Parameter | Specification |
|---|---|
| Part Number | 4644.026.365 |
| Series | WG 200 (WG200/555/5) |
| Assembly Type | Complete Powershift Unit |
| Weight (approx.) | 185 kg (408 lbs) |
| Housing Material | High-strength cast iron |
| OEM Reference | ZF 6 WG 200 |
| Input Spline | SAE 14T (standard) |
| Output Flange | DIN 5480 (compatible with 4644309001: OUTPUT FLANGE) |
| Sealing System | Includes 0634306323: O-RING kit |
Compatibility
This 4644.026.365 assembly is engineered for the ZF WG 200 series, specifically the 6 WG 200(555/5) variant. It is directly compatible with WG180, WG200, and WG210 transmissions that share the same 555/5 gear ratio set. The unit mates with the 4644101249: TRANSMISSION HOUSING and the 4644301402: TRANSMISSION HOUSING for proper alignment. For final assembly, the 4644301298: COVER PLATE seals the rear cavity. Always verify your transmission model tag before ordering.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644101249 | TRANSMISSION HOUSING | Main structural case for gear support |
| 4644301402 | TRANSMISSION HOUSING | Alternative housing variant for WG200 |
| 4644301298 | COVER PLATE | Seals rear access opening |
| 0634306323 | O-RING | Hydraulic seal between housing sections |
| 0636305026 | SCREW PLUG | Oil drain/fill port closure |
| 4644301279 | SCREEN SHEET | Filter mesh for hydraulic circuit |
| 4644301088 | SEALING CAP | Protects unused ports during storage |
| 4644298503 | REPAIR KIT | Gasket and seal overhaul set |
| 4644309001 | OUTPUT FLANGE | Driveline connection point |
| 4475280079 | SCREW PLUG | Secondary port plug (M22 thread) |
