Overview
The ZF 4644.306.562 VALVE BLOCK is a critical hydraulic control component engineered for the WG200 and WG201 series transmissions. This OEM genuine part acts as the central distribution hub for transmission fluid, directing oil pressure to actuate clutches and regulate gear shifts. Located within the valve body assembly, the SKU 4644.306.562 precisely meters hydraulic flow to ensure smooth engagement and disengagement of planetary gear sets. When paired with a properly sealed TRANSMISSION HOUSING, this valve block maintains the exact pressure thresholds required for reliable operation in heavy-duty industrial applications.
Symptoms of Failure
- Erratic or delayed gear engagement: Worn internal spools or clogged passages in the 4644.306.562 cause hesitation when shifting from neutral to drive or reverse, often accompanied by harsh engagement.
- Transmission fluid leaks at the valve body interface: Degraded sealing surfaces or cracked castings allow pressurized oil to escape, leaving puddles under the bell housing and reducing system pressure.
- Intermittent gear slipping under load: A failing valve block fails to maintain clutch pack pressure, causing the transmission to momentarily lose power during uphill climbs or heavy towing.
- Erratic shift patterns or limp mode activation: Contaminated or worn valve block passages disrupt shift timing, triggering fault codes and forcing the transmission into a protective reduced-power state.
Technical Specifications
| Specification | Detail |
|---|---|
| Part Number | 4644.306.562 |
| Material | High-strength aluminum alloy with anodized finish |
| Weight | 1.85 kg (4.08 lbs) |
| Dimensions (L x W x H) | 210 mm x 140 mm x 55 mm |
| OEM Reference | ZF 4644.306.562 |
| Fluid Ports | 8 hydraulic passages with O-ring grooves |
| Operating Pressure | 12–18 bar (174–261 psi) |
Compatibility
This valve block is designed for ZF WG series transmissions, specifically the WG180, WG200, and WG201 models. It also fits select WG65 series variants where the hydraulic control architecture matches. The 4644.306.562 interfaces directly with the OUTPUT shaft assembly and the OUTPUT FLANGE, ensuring proper oil distribution to the final drive. Secure mounting is achieved using HEXAGON SCREW fasteners, which must be torqued to factory specifications to prevent fluid bypass.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4616105402 | OUTPUT | Transfers rotational force from the transmission to the driveline |
| 4005303005 | OUTPUT FLANGE | Connects the output shaft to the driveshaft yoke |
| 4616101119 | TRANSMISSION HOUSING | Encloses and protects internal gear sets and hydraulic circuits |
| 0636011038 | HEXAGON SCREW | Secures valve block to the transmission housing |
| 0636011118 | HEXAGON SCREW | Fastens output flange to output shaft |
| 0636016015 | HEXAGON SCREW | Mounts auxiliary brackets to the transmission case |
| 0631306085 | CYLINDRICAL PIN | Aligns valve block and housing during assembly |
| 0634313118 | O-RING | Seals hydraulic ports between valve block and housing |
| 0636304019 | SCREW PLUG | Closes unused oil passages in the valve block |
| 0634801152 | SEALING RING | Prevents fluid leaks at screw plug interfaces |
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