Overview
The ZF 4644.026.386 6 WG 200 Powershift Transmission Assembly is a complete, fully assembled unit designed for heavy-duty off-highway applications. This integral assembly serves as the core power transfer module within the WG 200 series, managing torque distribution across six forward speeds. The SKU 4644.026.386 replaces the need for individual component sourcing, providing a drop-in solution for major overhauls. It sits directly between the engine flywheel housing and the final drive, incorporating the main shaft, clutch packs, and valve body. For optimal sealing, this unit is paired with a TRANSMISSION HOUSING and a TRANSMISSION HOUSING to ensure structural integrity under high load cycles.
Symptoms of Failure
- Erratic gear engagement or slipping under load: Worn clutch discs or degraded seals within the 4644.026.386 assembly cause delayed or incomplete shifts, particularly when transitioning from neutral to forward.
- External oil seepage at the bell housing interface: Cracks or fatigue in the main casing lead to fluid loss, often visible as drips near the mounting flange. This can be exacerbated by a failing O-RING at the cover joint.
- Unusual whining or grinding noises during operation: Bearing wear or planetary gear damage inside the complete unit produces metallic sounds that intensify with RPM, indicating imminent internal failure.
- Overheating and burnt transmission fluid odor: Restricted oil flow from a clogged COVER PLATE or internal debris causes thermal breakdown, leading to varnish buildup and reduced hydraulic pressure.
Technical Specifications
| Parameter | Value |
|---|---|
| Assembly Weight (dry) | 185 kg (408 lbs) |
| Overall Length | 620 mm |
| Overall Width | 480 mm |
| Overall Height | 410 mm |
| Housing Material | High-strength cast iron (GGG-40) |
| OEM Reference | ZF 4644.026.386 |
| Fluid Capacity | 14.5 liters (SAE 10W-30) |
| Max Input Torque | 1,200 Nm |
| Bolt Torque (housing) | 120 Nm (M12 bolts) |
Compatibility
This complete unit is engineered for the ZF WG 200 series, specifically the 6 WG 200 variant. It is also backward-compatible with earlier WG 180 models when used with a modified TRANSMISSION HOUSING adapter. The assembly fits ZF transmissions found in loaders, graders, and compactors from manufacturers such as Case, Volvo, and JCB. It is not cross-compatible with the WG 120 or WG 310 series without significant rework.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644101249 | TRANSMISSION HOUSING | Encloses gear train and supports shaft alignment |
| 4644301402 | TRANSMISSION HOUSING | Alternate housing variant for specific bell housing patterns |
| 4644301298 | COVER PLATE | Seals the clutch access port and guides oil flow |
| 0634306323 | O-RING | Prevents fluid leaks at housing-to-cover interface |
| 0636305026 | SCREW PLUG | Seals drain and fill ports |
| 4644301279 | SCREEN SHEET | Filters debris from hydraulic fluid |
| 4644301088 | SEALING CAP | Protects pressure test ports from contamination |
| 4644298503 | REPAIR KIT | Contains gaskets, seals, and o-rings for overhaul |
| 4475280079 | SCREW PLUG | Magnetic plug for ferrous debris capture |
| 4644121150 | OIL PIPE | Routes lubrication to planetary gearsets |
