Overview
This is the ZF 4644.026.302 6 WG 200 (555/5) Powershift Transmission Assembly, a complete unit engineered for heavy-duty off-highway applications. As a fully assembled drop-in replacement, this component integrates the torque converter, clutch packs, and planetary gear sets into a single, ready-to-install package. The SKU 4644.026.302 specifically designates a WG 200 series unit with a 555/5 gear ratio configuration, optimized for loaders, graders, and industrial tractors requiring precise power modulation under high torque loads. This assembly sits as the primary drivetrain component, directly coupling the engine to the final drive, and is critical for maintaining operational uptime in demanding environments.
Symptoms of Failure
When the ZF 4644.026.302 begins to degrade, operators will notice distinct performance issues. Recognizing these signs early can prevent catastrophic driveline damage.
- Delayed or harsh engagement when shifting between forward and reverse: A worn clutch pack or degraded seals within the assembly cause a noticeable lag or a jarring “clunk” during directional changes, often accompanied by a momentary loss of tractive effort.
- Progressive gear slipping under load: The transmission may appear to “hunt” for gears or lose power when climbing grades or pushing heavy material. This is a classic indicator of internal hydraulic pressure loss or worn friction discs.
- External oil leaks from the main housing or converter area: Weeping or pooling transmission fluid around the bell housing or output flange indicates compromised gaskets or seal rings. This leads to low fluid levels and eventual overheating.
- Unusual whining or grinding noises during operation: A high-pitched whine in neutral or a low grinding sound in gear points to bearing failure or planetary gear damage, requiring immediate attention to avoid total seizure.
Technical Specifications
| Specification | Value |
|---|---|
| Part Number / SKU | 4644.026.302 |
| Assembly Type | Complete Powershift Transmission Unit |
| Series | WG 200 (6 WG 200 variant) |
| Gear Ratio Configuration | 555/5 |
| Dry Weight (Approx.) | 385 kg (849 lbs) |
| Overall Length | 785 mm |
| Input Torque Capacity | 1,100 Nm (811 lb-ft) |
| Housing Material | High-Strength Cast Iron (GGG-40) |
| OEM Reference | ZF Friedrichshafen AG |
Compatibility
This complete assembly is engineered for the ZF WG 200 series platform. While the 4644.026.302 is a direct fit for the 6 WG 200 (555/5) configuration, it shares core architecture with other WG family transmissions. It is compatible with the following ZF models and their respective applications:
- ZF WG 180: Limited compatibility; requires verification of bell housing pattern and torque converter size.
- ZF WG 200: Primary application. Direct fit for all 6-speed variants (6 WG 200).
- ZF WG 210: Mechanically similar but may require different output flanges or adaptor plates.
- ZF Ergopower (e.g., 6HP series): Not compatible due to different hydraulic control logic and mounting dimensions.
Always cross-reference your existing unit’s serial number with the 4644.026.302 specifications to ensure correct spline count and PTO drive alignment.
