Overview
The ZF 4644.026.377 6 WG 200 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 elements into a single, ready-to-install package. As a core component of the WG 200 series, it manages torque distribution across six forward speeds, ensuring smooth power delivery under extreme loads. The SKU 4644.026.377 replaces worn or failed assemblies, restoring original ZF performance. This unit mounts directly to the TRANSMISSION HOUSING (4644101249) and mates with the TRANSMISSION HOUSING (4644301402) to form the sealed drivetrain cavity.
Symptoms of Failure
- Delayed or harsh gear engagement: When the assembly wears, hydraulic pressure drops, causing a noticeable lag or clunk when shifting between forward and reverse. This often points to internal clutch pack degradation.
- Torque converter shudder under load: A vibration or shudder during acceleration, especially on inclines, indicates worn stator or turbine components within the 6 WG 200 assembly.
- External oil seepage at the housing joint: Leaks around the mating surface between the assembly and the COVER PLATE (4644301298) signal a failing gasket or seal. The O-RING (0634306323) often requires replacement during installation to prevent future leaks.
- Erratic shifting or neutral creep: Inconsistent gear holding or the vehicle creeping in neutral suggests internal valve body or piston seal failure within the assembly.
Technical Specifications
| Parameter | Specification |
|---|---|
| OEM Part Number | 4644.026.377 |
| Series | WG 200 (6 WG 200) |
| Assembly Type | Complete Powershift Transmission Assembly |
| Dry Weight (approx.) | 185 kg (408 lbs) |
| Overall Length | 620 mm |
| Overall Width | 480 mm |
| Overall Height | 510 mm |
| Housing Material | High-Grade Cast Iron |
| Clutch Pack Material | Sintered Bronze / Steel |
| Max Input Torque | 1,200 Nm |
| OEM Reference | ZF 4644.026.377 |
Compatibility
This complete assembly is engineered for the ZF WG 200 series, specifically the 6-speed WG 200 variant. It is directly compatible with WG 180, WG 200, and WG 210 models that share the same bell-housing bolt pattern and input shaft spline count. The unit also fits select ZF 4 WG 200 and 6 WG 200 configurations used in telehandlers, wheel loaders, and industrial tractors. Always verify the serial number against your existing transmission to confirm fitment.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644101249 | TRANSMISSION HOUSING | Main structural casing for gear and shaft support |
| 4644301402 | TRANSMISSION HOUSING | Secondary housing for clutch pack and valve body |
| 4644301298 | COVER PLATE | Seals the rear of the transmission assembly |
| 0634306323 | O-RING | Seals fluid passages between housing sections |
| 0636305026 | SCREW PLUG | Closes oil drain and fill ports |
| 4644301279 | SCREEN SHEET | Filters debris from hydraulic oil flow |
| 4644301088 | SEALING CAP | Protects exposed shaft ends from contamination |
| 4644109044 | PARKING BRAKE | Spring-applied, hydraulically released brake unit |
| 0501211070 | BRAKE | Service brake disc assembly for wheel-end braking |
| 0501317036 | PISTON | Hydraulic piston for clutch or brake actuation |
