Overview
The ZF 4644.026.198 6 WG 200(555/5) Powershift Transmission Assembly represents a complete, factory-grade replacement unit designed for heavy-duty off-highway applications. This assembly integrates the torque converter, planetary gear sets, and hydraulic control system into a single, ready-to-install package. As the core power delivery module within the WG 200 Series, it manages gear ratio changes under load without interrupting power flow, making it essential for wheel loaders, dozers, and material handlers. The SKU 4644.026.198 specifically denotes a 6-speed forward, 3-speed reverse configuration with a 555/5 torque converter ratio, ensuring precise match for original equipment specifications.
Symptoms of Failure
When the ZF 4644.026.198 unit begins to degrade, operators will notice distinct performance issues. Recognizing these signs early can prevent catastrophic drivetrain damage and costly downtime.
- Delayed or harsh engagement when shifting from neutral to forward or reverse: This indicates internal seal wear or clutch pack degradation within the powershift section, often accompanied by a noticeable “clunk” or hesitation.
- Progressive oil leaks around the transmission housing or output flange: Worn shaft seals or cracked housing gaskets allow hydraulic fluid to escape, leading to low oil pressure and eventual gear slipping. Look for puddles under the bell housing area.
- Erratic or surging power delivery under load: A failing torque converter stator or worn valve body spools can cause the transmission to hunt between gears or lose torque multiplication when pushing heavy loads.
- Unusual whining or grinding noises during operation: Bearing failure in the planetary gear sets or damaged gear teeth produce metallic sounds that intensify with engine RPM, signaling imminent internal mechanical failure.
Technical Specifications
| Parameter | Specification |
|---|---|
| Part Number / SKU | 4644.026.198 |
| Series | WG 200 (6 WG 200) |
| Configuration | 6 Forward / 3 Reverse Powershift |
| Torque Converter Ratio | 555/5 (2.85:1 stall ratio) |
| Overall Length (approx.) | 685 mm (27.0 in) |
| Dry Weight | 385 kg (849 lbs) |
| Housing Material | High-strength cast iron (GGG-40) |
| Max Input Torque | 1,200 Nm (885 lb-ft) |
| OEM Reference | ZF 4644.026.198 / 0501.302.007 |
Compatibility
This complete assembly is engineered for the ZF WG 200 Series transmission family. It is a direct replacement for units originally installed in the following models and their variants:
- ZF WG 180 (retrofit compatible with adapter plate modifications)
- ZF WG 200 (primary application, including 6 WG 200 and 4 WG 200 variants)
- ZF WG 210 (limited compatibility; verify bell housing pattern)
- ZF Ergopower 200 (select models using the 555/5 torque converter)
Always cross-reference your existing transmission’s serial number with the 4644.026.198 specification to confirm hydraulic valve body and clutch pack configuration. This unit is not compatible with the WG 150 or WG 250 series without significant mechanical rework.
