Overview
The ZF 4644.026.069 6 WG 200(555/5) Powershift Transmission Assembly is a complete, factory-matched unit designed for heavy-duty off-highway applications. This assembly integrates the torque converter, clutch packs, and planetary gear sets into a single, ready-to-install package. As a core component of the WG 200 Series, it manages power distribution from the engine to the driveline, enabling smooth, clutchless shifting under load. The SKU 4644.026.069 specifically denotes a 6-speed configuration with a 555/5 gear ratio set, optimized for high-torque, low-speed operations such as those found in articulated dump trucks and large wheel loaders. This unit replaces worn or failed assemblies to restore original performance and reliability.
Symptoms of Failure
When the ZF 4644.026.069 begins to degrade, operators typically notice these specific failure modes:
- Delayed or harsh engagement: A noticeable lag when shifting from neutral to forward or reverse, often accompanied by a jarring clunk. This indicates worn clutch pack friction discs or degraded seals within the valve body.
- Transmission overheating under light load: If the unit runs hotter than normal during routine operation, it suggests internal leakage in the torque converter or pump, reducing hydraulic efficiency and cooling flow.
- Intermittent gear slipping under load: The transmission may momentarily lose power during a grade climb or when applying heavy throttle, pointing to worn planetary gear bearings or a failing one-way clutch.
- External oil seepage from the bell housing: Fluid leaks near the engine-transmission interface often stem from a degraded front pump seal or a cracked converter housing, leading to low fluid levels and eventual failure.
Technical Specifications
| Parameter | Value |
|---|---|
| Assembly Type | Complete Powershift Transmission |
| OEM Reference | ZF 4644.026.069 |
| Series | WG 200 (6 WG 200) |
| Number of Speeds | 6 Forward / 1 Reverse |
| Gear Ratio Set | 555/5 |
| Dry Weight (approx.) | 385 kg (849 lbs) |
| Overall Length | 785 mm |
| Housing Material | High-Strength Cast Iron |
| Torque Converter Diameter | 380 mm |
| Max Input Torque | 1,200 Nm |
Compatibility
This ZF 4644.026.069 assembly is engineered for the WG 200 Series transmission family. It is directly compatible with the following ZF models and their derivatives:
- ZF 6 WG 200 (all sub-variants using the 555/5 ratio)
- ZF WG 180 (when retrofitted with the 200-series bell housing and torque converter)
- ZF WG 210 (limited compatibility; verify input flange and PTO mount)
- ZF WG 160 (not recommended without full driveline modification)
Always cross-reference the original transmission tag and vehicle OEM part number before installation. This unit is a direct replacement for ZF 4644.026.069 and supersedes earlier part numbers 4644.026.067 and 4644.026.068.
