Overview
The ZF 4616.120.403 PRESSURE REGULATOR is a precision-engineered hydraulic control component designed exclusively for the WG 65 series of off-highway transmissions. This OEM genuine part modulates oil flow to maintain consistent clutch and brake application pressure, ensuring smooth power delivery under heavy load. Positioned within the valve body assembly, the regulator directly interfaces with the TRANSMISSION HOUSING (4616101111) to stabilize system pressure. The SKU 4616.120.403 is manufactured to ZF’s exacting tolerances, making it a critical element for preventing pressure spikes that can damage internal seals and bearings.
Symptoms of Failure
- Erratic gear engagement or delayed shifting – A worn regulator causes inconsistent hydraulic pressure, leading to harsh or sluggish gear changes, especially when the transmission is cold.
- Internal oil leaks near the valve body – Degraded sealing surfaces on the 4616.120.403 allow ATF to bypass, resulting in visible drips or puddles under the HOUSING (4616301304) assembly.
- Transmission overheating under load – Failed pressure regulation forces the torque converter to work harder, generating excess heat that accelerates fluid breakdown.
- Clutch slip during uphill or loaded operation – Insufficient hold pressure from a faulty regulator causes clutches to slip, reducing torque transfer and causing RPM flare.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 4616.120.403 |
| Material | Hardened steel with zinc-nickel coating |
| Weight | 0.28 kg (0.62 lbs) |
| Overall Length | 62 mm |
| Body Diameter | 28 mm |
| OEM Reference | ZF 4616.120.403 |
| Operating Pressure Range | 8–22 bar (116–319 psi) |
| Seal Type | PTFE lip seal |
Compatibility
This pressure regulator is engineered for the ZF WG65 transmission series, which includes models such as WG65, WG80, WG100, WG120, WG150, WG180, and WG200. It is also compatible with select variants of the ZF 4WG and 5WG off-highway gearboxes used in forklifts, wheel loaders, and agricultural tractors. Always verify the part number 4616.120.403 against your transmission’s valve body configuration before installation. For secure mounting, pair this regulator with the HEXAGON SCREW (0636011118) and ensure the HOUSING (4616301309) mating surface is clean.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4616101111 | TRANSMISSION HOUSING | Main structural casing for gear and valve assembly |
| 0636011118 | HEXAGON SCREW | Fastens valve body to housing |
| 4616301304 | HOUSING | Encloses clutch pack and hydraulic circuits |
| 4616301309 | HOUSING | Secondary housing for oil distribution |
| 0636011038 | HEXAGON SCREW | M6 mounting bolt for valve cover |
| 0636016015 | HEXAGON SCREW | M8 bolt for housing flange |
| 0631306085 | CYLINDRICAL PIN | Alignment dowel for valve body positioning |
| 0634313118 | O-RING | Seals regulator bore against leakage |
| 0636304019 | SCREW PLUG | Closes test port in valve body |
| 0634801152 | SEALING RING | Copper washer for plug sealing |
