Overview
The ZF 4644.026.254 6 WG 200(400/3) Powershift Transmission Assembly is a complete, factory-matched unit designed for heavy-duty off-highway applications. As a core component of the WG 200 series, this assembly integrates the torque converter, planetary gear sets, and hydraulic control module into a single, ready-to-install package. The SKU 4644.026.254 specifically denotes a 6-speed configuration with a 400/3 torque converter ratio, optimized for loaders, graders, and material handlers requiring precise power modulation. This unit replaces worn or failed assemblies to restore original shift quality and driveline efficiency.
Symptoms of Failure
When the ZF 4644.026.254 assembly degrades, operators typically notice these specific failure modes:
- Delayed or harsh engagement – A pronounced lag when shifting from neutral to forward or reverse, often accompanied by a jarring clunk, indicating worn clutch packs or hydraulic pressure loss.
- Torque converter shudder – A vibration or surging sensation during low-speed maneuvering, especially under load, pointing to stator or turbine damage within the 400/3 converter.
- External oil seepage at the bell housing – Visible fluid accumulation around the transmission-to-engine interface, typically caused by a degraded front pump seal or cracked converter housing.
- Intermittent gear slip under load – The transmission momentarily loses drive power when climbing grades or pushing heavy material, a classic sign of worn planetary gear bearings or failed sprag clutches.
Technical Specifications
| Parameter | Specification |
|---|---|
| Assembly Type | Complete Powershift Unit (6 WG 200) |
| SKU / Part Number | 4644.026.254 |
| Torque Converter Ratio | 400/3 (Stall Torque Ratio: 2.8:1) |
| Number of Speeds | 6 Forward / 3 Reverse |
| Dry Weight (Approx.) | 385 kg (849 lbs) |
| Housing Material | High-strength cast iron (GGG-40) |
| OEM Reference | ZF 1328 301 001 (Superseded) |
| Input Spline | SAE 14″ (10-spline, 2.5″ pilot) |
| Fluid Capacity | 22 liters (ZF TE-ML 03 spec) |
Compatibility
This complete assembly is engineered for the ZF WG 200 series transmission family. Based on its 6-speed, 400/3 converter configuration, it is directly compatible with the following models and their derivatives:
- ZF WG 200 – All standard-duty variants (6 WG 200, 4 WG 200)
- ZF WG 180 – Limited compatibility when using an adapter plate for the torque converter housing (verify input spline count)
- ZF WG 210 – Direct fit for units requiring a 400/3 stall ratio; check hydraulic valve body orientation
- ZF 6 WG 200 (400/3) – Exact match for OEM installations in Volvo L120G, Caterpillar 950H, and Komatsu WA380-8 loaders
Note: Always cross-reference the transmission serial number and vehicle manufacturer’s parts catalog before installation. This assembly does not include the external wiring harness or shift controller.
