Overview
The ZF 4644.311.172 DRIVER is a critical rotational component engineered for the WG 201 Series transmission family. This OEM genuine part functions as the primary torque-transfer interface within the clutch pack assembly, converting hydraulic pressure into mechanical motion to engage and disengage gear sets. Identified by SKU 4644.311.172, this driver sits directly on the main shaft and interfaces with the transmission housing to ensure precise gear selection under heavy-duty industrial loads. Manufactured to ZF’s original specifications, it guarantees exact fitment and long service life in demanding environments.
Symptoms of Failure
- Delayed or harsh gear engagement: When the 4644.311.172 driver wears, operators often experience a noticeable lag or jarring shift when moving between forward and reverse gears, particularly under load.
- Transmission slipping under torque: A worn driver can cause intermittent power loss during acceleration, as the clutch pack fails to lock fully, leading to RPM flare without corresponding vehicle speed increase.
- Metallic grinding noises from the bell housing: Excessive wear on the driver’s splines or friction surfaces produces a distinct grinding or rattling sound during gear changes, indicating imminent internal damage.
- Hydraulic fluid contamination: As the driver degrades, metal particles can shed into the transmission oil, visible as glitter in the fluid during routine checks, often accompanied by erratic shift behavior.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 4644.311.172 |
| OEM Reference | ZF 4644.311.172 |
| Material | Case-hardened alloy steel |
| Outer Diameter | ~145 mm |
| Inner Diameter | ~38 mm |
| Thickness | ~22 mm |
| Weight | 0.85 kg |
| Spline Count | 24 internal splines |
| Surface Finish | Phosphate coated |
Compatibility
This driver is specifically designed for the ZF WG 201 Series, including models WG180, WG200, WG210, and WG220. It is a direct replacement for transmissions used in construction equipment, agricultural machinery, and material handling vehicles. The 4644.311.172 driver is also compatible with certain WG 200 Series variants produced between 2005 and 2018. Always verify your transmission’s serial number against the OEM parts catalog before ordering.
During installation, this driver works in concert with the TRANSMISSION HOUSING (4644101160) and the TRANSMISSION HOUSING (4644301323) to create a sealed assembly. The THREADED BUSH (4644301189) secures the driver’s axial position, while the SCREW PLUG (4475280043) seals the hydraulic circuit. For a complete rebuild, also consider the O-RING (0634306198) and TYPE PLATE (0730365067) for identification.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644101160 | TRANSMISSION HOUSING | Encloses gear train and supports shafts |
| 4644301323 | TRANSMISSION HOUSING | Alternate housing variant for WG201 |
| 4644301189 | THREADED BUSH | Positions and retains driver assembly |
| 4475280043 | SCREW PLUG | Seals hydraulic pressure ports |
| 0634306198 | O-RING | Prevents fluid leaks at housing joints |
| 0730365067 | TYPE PLATE | Provides model and serial number identification |
| 4644301161 | COVER PLATE | Protects internal components from debris |
| 0636100621 | HEXAGON SCREW | Fastens housing sections together |
| 0631610020 | SET SCREW | Locks adjustment mechanisms in place |
| 0501218540 | BREATHER | Equalizes internal pressure and vents moisture |
