Overview
The ZF 4644.301.257 ADAPTER is a precision-machined coupling component engineered for the WG150, WG180, and WG200 series transmissions. This OEM genuine part serves as the critical interface between the transmission housing and the shift system assembly, ensuring proper alignment and torque transfer during gear engagement. The SKU 4644.301.257 is specifically designed to withstand high axial loads and thermal expansion within the transmission casing. When installed alongside a TRANSMISSION HOUSING (4642101109) or a TRANSMISSION HOUSING (4642301205), this adapter guarantees a sealed, vibration-resistant connection that maintains hydraulic pressure integrity.
Symptoms of Failure
- Oil seepage at the adapter joint: Worn sealing surfaces on the 4644.301.257 adapter allow transmission fluid to escape, often visible as wet spots near the housing interface.
- Intermittent gear engagement hesitation: A failing adapter causes misalignment between the shift fork and the clutch pack, leading to delayed or rough shifting under load.
- Metallic rattling from the bell housing area: Loose fitment of the adapter against the GROOVED STUD (0631311009) produces a distinct chatter during acceleration or deceleration.
- Increased driveline backlash: Excessive play in the adapter bore results in a noticeable clunk when transitioning between forward and reverse gears.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 4644.301.257 |
| Material | Hardened alloy steel (DIN 1.7131) |
| Outer Diameter | 98.5 mm |
| Inner Diameter | 42.0 mm |
| Overall Length | 65.3 mm |
| Weight | 0.48 kg |
| OEM Reference | ZF 4644.301.257 |
| Surface Finish | Zinc-nickel plated (ISO 2081) |
Compatibility
This adapter is factory-specified for ZF WG150, WG180, and WG200 series transmissions used in medium-duty commercial vehicles, agricultural tractors, and construction equipment. It directly replaces the original adapter in models with serial numbers starting between 2015 and 2023. The 4644.301.257 is also compatible with earlier WG180 variants when paired with the correct TYPE PLATE (0730365125) for identification. For WG200 applications, verify that the shift system (e.g., SHIFT SYSTEM (4644106231)) uses the same bolt pattern as this adapter.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4642101109 | TRANSMISSION HOUSING | Main structural casing for gear train |
| 4642301205 | TRANSMISSION HOUSING | Alternate housing for WG180 series |
| 0730365125 | TYPE PLATE | Identification plate for transmission specs |
| 0631311009 | GROOVED STUD | Alignment dowel for adapter mounting |
| 4642301168 | SCREEN SHEET | Filter mesh for hydraulic circuit |
| 4642301169 | SCREEN SHEET | Fine-mesh screen for oil return |
| 0636100621 | HEXAGON SCREW | Fastener for adapter-to-housing joint |
| 4642301186 | SCREEN SHEET | Secondary filter element |
| 4644106231 | SHIFT SYSTEM | Gear selection mechanism |
| 4644306470 | GASKET | Seal between adapter and housing |
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