Overview
The ZF 4644.004.233 4 WG 180(555) Powershift Transmission Assembly is a complete, fully assembled unit designed for heavy-duty off-highway applications. This complete assembly integrates the core hydraulic and mechanical components required for reliable power distribution in ZF’s WG 180 series. The SKU 4644.004.233 serves as a direct replacement for the original factory assembly, ensuring seamless integration with the transmission housing. It sits at the heart of the drivetrain, managing torque flow and clutch engagement. When replacing this unit, it is critical to inspect the TRANSMISSION HOUSING (4644101249) for cracks or wear, as the assembly mounts directly into this structure.
Symptoms of Failure
- Delayed or harsh gear engagement: If the complete unit wears internally, operators often experience a noticeable lag when shifting from neutral to forward or reverse, followed by a jarring engagement. This is a common sign of internal seal degradation.
- Intermittent power loss under load: A failing assembly may cause the vehicle to lose pulling power on inclines or during heavy loading, often accompanied by a whining noise from the transmission housing.
- External hydraulic oil leaks: Deteriorated gaskets or cracked components within the assembly can lead to fluid seeping from the bell housing area. Check the O-RING (0634306323) for signs of hardening if leaks are present.
- Overheating transmission fluid: Internal slippage due to worn clutches generates excessive heat, triggering warning lights or burnt fluid odor.
Technical Specifications
| Parameter | Specification |
|---|---|
| Part Number | 4644.004.233 |
| Assembly Type | Complete Powershift Unit (4 WG 180/555) |
| Dry Weight (approx.) | 185 kg (408 lbs) |
| Housing Material | High-strength cast iron |
| OEM Reference | ZF 4644.004.233 |
| Overall Length | 620 mm |
| Overall Width | 480 mm |
| Overall Height | 510 mm |
| Fluid Capacity | 12.5 liters (approximate) |
Compatibility
This complete assembly is engineered primarily for the ZF WG 180 series transmissions, including the 4 WG 180(555) variant. It is also compatible with select WG 200 series models that share the same mounting flange and input shaft configuration. For proper fitment, verify the transmission serial number against the housing casting. The assembly works in conjunction with the TRANSMISSION HOUSING (4644301402) and the COVER PLATE (4644301298) to form a sealed unit. It is commonly used in ZF 4WG-180, 4WG-200, and 4WG-210 systems found in telescopic handlers, wheel loaders, and agricultural tractors.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644101249 | TRANSMISSION HOUSING | Main structural casing for the gear train |
| 4644301402 | TRANSMISSION HOUSING | Alternative housing variant for WG180 |
| 4644301298 | COVER PLATE | Seals the rear of the transmission housing |
| 0634306323 | O-RING | Prevents fluid leaks at housing joints |
| 0636305026 | SCREW PLUG | Seals oil drain/fill ports |
| 4644301279 | SCREEN SHEET | Filters debris from hydraulic fluid |
| 4644301088 | SEALING CAP | Protects exposed ports during storage |
| 4644159347 | SHIFT SYSTEM | Controls clutch pack engagement |
| 4475280036 | SCREW-IN SLEEVE | Provides threaded mounting points |
| 4644306511 | GEAR SHIFT HOUSING | Encloses shift mechanism |
