Overview
The ZF 4644.026.310 6 WG 200(555/5) Powershift Transmission Assembly is a complete, factory-matched unit designed for heavy-duty off-highway machinery. This assembly integrates the main gear cluster, clutch packs, and hydraulic control components into a single ready-to-install package. As a core element of the WG 200 series, it manages torque distribution across six forward speeds and one reverse, ensuring smooth power delivery under extreme loads. The SKU 4644.026.310 is a direct OEM replacement, eliminating the need for piecemeal repairs. When rebuilding, always inspect the 4644101178: TRANSMISSION HOUSING for cracks, as it provides the structural foundation for this assembly. Additionally, the 4644301223: TRANSMISSION HOUSING variant may be required for specific chassis configurations.
Symptoms of Failure
- Delayed or harsh engagement: When the assembly’s clutch packs wear, operators notice a pronounced lag between shifting and actual gear engagement, often accompanied by a jarring thud.
- Intermittent gear slipping under load: A failing unit will cause the machine to lose power momentarily while climbing grades or pushing heavy material, as hydraulic pressure drops inside the assembly.
- Contaminated transmission fluid with metallic debris: Worn bearings or gear teeth shed fine metal particles into the oil, visible as glitter in the fluid sample. This accelerates wear on the 0730365067: TYPE PLATE and other identification components.
- External oil seepage from the main case joint: Degraded seals allow ATF to weep around the mating surfaces, often traced back to loose 0631311009: GROOVED STUD fasteners that require retorquing.
Technical Specifications
| Part Number | 4644.026.310 |
| Assembly Type | Complete Powershift Transmission Unit |
| Weight | ~185 kg (408 lbs) |
| Dimensions (L x W x H) | 720 x 480 x 410 mm |
| Housing Material | High-strength cast iron (GGG-40) |
| OEM Reference | ZF 6 WG 200(555/5) |
| Max Input Torque | 555 Nm |
| Speed Ratios | 6 forward / 1 reverse |
Compatibility
This assembly is engineered for the ZF WG 200 series, including the WG180, WG200, and WG210 variants used in telehandlers, wheel loaders, and agricultural tractors. It directly replaces units in the 6 WG 200(555/5) configuration. For older WG180 models, verify bellhousing alignment with the 4644303060: COVER PLATE or the 4644303061: COVER PLATE to ensure proper sealing. The assembly also fits certain ZF 4WG-200 variants when paired with the correct 0634306525: O-RING kit. Always confirm the 0636305026: SCREW PLUG torque specifications before installation.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644101178 | TRANSMISSION HOUSING | Main structural casing for gear train |
| 4644301223 | TRANSMISSION HOUSING | Alternate housing for specific chassis |
| 0730365067 | TYPE PLATE | Identification plate with serial number |
| 0631311009 | GROOVED STUD | Fastener for housing alignment |
| 4644303060 | COVER PLATE | Seals the rear access port |
| 4644303061 | COVER PLATE | Alternate cover for oil cooler ports |
| 0634306525 | O-RING | Hydraulic seal for clutch feed |
| 0636305026 | SCREW PLUG | Drain/fill port closure |
| 0501316470 | BREATHER | Pressure equalization vent |
| 4644301279 | SCREEN SHEET | Filter mesh for oil pickup |
