Overview
The ZF 4644.026.408 6 WG 200 Powershift Transmission Assembly is a complete, factory-grade unit designed for heavy-duty off-highway machinery. This assembly integrates the full clutch pack, planetary gear sets, and hydraulic control system into a single, ready-to-install package. As the core of the WG 200 series, it manages torque distribution across six forward speeds, ensuring smooth power delivery under extreme loads. The SKU 4644.026.408 identifies this as a direct OEM replacement, eliminating the need for partial rebuilds. It sits directly between the engine flywheel housing and the final drive, serving as the primary power transfer module. For maximum sealing integrity, always pair this assembly with a new TRANSMISSION HOUSING (part 4644101249) to prevent contamination from debris ingress.
Symptoms of Failure
- Delayed engagement or gear slipping under load: When internal clutch discs wear, the transmission hesitates before engaging forward or reverse, often accompanied by a momentary loss of power during uphill operation.
- External oil leaks near the bell housing: Cracks in the main casing or degraded O-RING (part 0634306323) cause fluid seepage, leaving visible puddles under the vehicle after shutdown.
- Erratic shifting or harsh engagement: Worn valve body components within the assembly produce sudden, jarring shifts instead of smooth transitions, indicating hydraulic pressure loss.
- Overheating transmission fluid: Internal friction from failing bearings generates excessive heat, triggering warning lights and a burnt odor from the dipstick.
Technical Specifications
| Parameter | Value |
|---|---|
| Assembly Weight | 185 kg (408 lbs) |
| Overall Length | 620 mm |
| Housing Material | High-strength cast iron (GGG-40) |
| Max Input Torque | 1,200 Nm |
| OEM Reference | ZF 4644.026.408 |
| Fluid Capacity | 14.5 liters (ZF TE-ML 03 spec) |
| Bolt Torque (housing) | 85 Nm ± 5 Nm |
Compatibility
This complete unit is engineered specifically for the ZF WG 200 series, including models WG 200, WG 210, and WG 220 used in telescopic handlers, wheel loaders, and agricultural tractors. It also fits select WG 180 variants when paired with an adapter TRANSMISSION HOUSING (part 4644301402). For proper sealing, the COVER PLATE (part 4644301298) must be installed on the rear face to protect the output shaft splines. Always verify your transmission serial number against ZF’s compatibility chart before ordering.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644101249 | TRANSMISSION HOUSING | Encloses gear train; provides mounting points |
| 4644301402 | TRANSMISSION HOUSING | Alternate housing for WG 180 adapter fit |
| 4644301298 | COVER PLATE | Seals rear output shaft opening |
| 0634306323 | O-RING | Prevents fluid leaks at housing joints |
| 0636305026 | SCREW PLUG | Seals drain/fill ports |
| 4644301279 | SCREEN SHEET | Filters debris from hydraulic fluid |
| 4644301088 | SEALING CAP | Protects unused ports during storage |
| 4644298503 | REPAIR KIT | Includes gaskets and seals for overhaul |
| 4475280079 | SCREW PLUG | High-torque plug for pressure test ports |
| 4644121150 | OIL PIPE | Routes lubricant to planetary gears |
