Overview
The ZF 4616.120.402 PRESSURE REGULATOR is a precision hydraulic control component engineered specifically for the WG65 series of off-highway transmissions. This OEM genuine part governs the modulation of hydraulic pressure within the valve body, ensuring consistent clutch engagement and torque converter lock-up. Installed directly in the transmission control unit, the 4616.120.402 acts as a critical gatekeeper for fluid flow, directly influencing shift quality and overall drivetrain efficiency. When paired with a robust 4616105413: OUTPUT shaft assembly, this regulator maintains the hydraulic balance required for heavy-duty operations in construction and agricultural machinery.
Symptoms of Failure
- Erratic or delayed gear engagement: A worn 4616.120.402 often causes hesitation when shifting from neutral to drive, particularly under load, as the valve fails to maintain precise pilot pressure.
- Torque converter shudder at low RPM: If the pressure regulator cannot stabilize line pressure, the converter lock-up clutch may slip intermittently, producing a noticeable vibration during acceleration.
- Hydraulic oil leaks near the valve body: Degraded sealing surfaces on the regulator allow ATF to bypass, leading to visible drips around the transmission housing and a drop in sump fluid level.
- Harsh or flared upshifts: Inconsistent pressure regulation results in abrupt clutch pack application or prolonged slip, often accompanied by a temporary RPM flare between gears.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 4616.120.402 |
| OEM Reference | ZF 4616.120.402 |
| Material | Hardened steel spool with anodized aluminum body |
| Operating Pressure Range | 8–22 bar (116–319 psi) |
| Weight | 0.34 kg (0.75 lbs) |
| Seal Type | Integrated PTFE backup rings |
| Compatible Fluid | ZF TE-ML 03 or Dexron III ATF |
Compatibility
This pressure regulator is a direct-fit component for the ZF WG65 transmission series, which includes models such as the WG65, WG80, WG100, WG120, WG150, WG180, and WG200. It is also commonly used in the WG65-based powertrains found in ZF’s Ecolife and Ecomat off-highway variants. For proper installation, ensure the 4616203017: OUTPUT FLANGE is torqued to specification, and verify that the 4616101117: TRANSMISSION HOUSING is free of debris. Secure the assembly using a 0636011038: HEXAGON SCREW to prevent vibration loosening.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4616105413 | OUTPUT | Transfers torque from the transmission to the driveline |
| 4616203017 | OUTPUT FLANGE | Connects output shaft to universal joint or yoke |
| 4616101117 | TRANSMISSION HOUSING | Encloses gear sets and valve body assembly |
| 0636011038 | HEXAGON SCREW | Fastens pressure regulator to valve body |
| 0636016015 | HEXAGON SCREW | Secures output flange to shaft |
| 0631306085 | CYLINDRICAL PIN | Aligns valve body components during assembly |
| 0634313118 | O-RING | Seals pressure regulator bore against leakage |
| 0732611049 | FILTER INSERT | Traps debris before fluid enters regulator |
| 0634303718 | O-RING | Seals output flange to housing |
| 0636610082 | STUD | Provides threaded mounting for housing covers |
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