Overview
This OEM genuine ZF 4657.120.005 PRESSURE REGULATOR is a critical hydraulic control component designed specifically for the WG 191 and WG 211 series transmissions. Positioned within the valve body assembly, this precision-machined regulator modulates hydraulic pressure to ensure consistent clutch and brake application during gear shifts. The SKU 4657.120.005 works in concert with the 0501211384: VALVE to maintain stable line pressure, preventing erratic shift behavior. When this pressure regulator fails, the entire hydraulic circuit becomes unstable, leading to delayed engagement and potential transmission damage.
Symptoms of Failure
- Erratic shift timing and gear slipping under load — A worn 4657.120.005 cannot maintain consistent pressure, causing the transmission to slip between gears, especially during uphill driving or towing.
- Delayed forward or reverse engagement — If the regulator sticks or leaks internally, you may experience a 2-3 second delay when shifting from Neutral to Drive or Reverse.
- Oil leaks around the valve body area — Degraded O-rings or a cracked regulator housing can cause ATF to seep past the 0630532183: INDENTED RING, leaving visible drips on the transmission pan.
- Harsh or flared upshifts — Fluctuating pressure from a failing regulator results in jarring shifts or momentary loss of power during acceleration.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number / SKU | 4657.120.005 |
| OEM Reference | ZF 4657.120.005 |
| Material | Hardened steel with corrosion-resistant coating |
| Overall Length | 85 mm (approx.) |
| Outer Diameter | 28 mm (approx.) |
| Weight | 0.18 kg (0.4 lbs) |
| Operating Pressure Range | 8–18 bar (116–261 psi) |
| Seal Type | Integrated O-ring (replacement recommended) |
Compatibility
This pressure regulator is engineered for the ZF WG 191 and WG 211 series transmissions, commonly found in medium-duty commercial vehicles, buses, and off-highway equipment. It is also compatible with the WG 180 and WG 200 series when used in conjunction with the 4656306145: PISTON and the 0732042767: COMPRESSION SPRING. Always verify your transmission model and valve body configuration before ordering.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 0501211384 | VALVE | Directs hydraulic flow within the valve body |
| 0630532183 | INDENTED RING | Secures valve components and prevents axial movement |
| 4656306145 | PISTON | Transmits hydraulic force to shift elements |
| 0732042767 | COMPRESSION SPRING | Provides return force for regulator and valve pistons |
| 0631612064 | SET SCREW | Adjusts valve travel limits |
| 0631610026 | SET SCREW | Secures pressure regulator in bore |
| 4657101049 | TRANSMISSION HOUSING | Main structural casing for gear train |
| 4657301130 | HOUS.FRONT SECT | Front section of transmission housing |
| 4657301131 | HOUSING REAR PART | Rear section of transmission housing |
| 0631306816 | CYLINDRICAL PIN | Alignment dowel for housing assembly |
Frequently Asked Questions
Q: How do I know if my ZF WG191 needs a new 4657.120.005 pressure regulator?
A: If you notice erratic shifting, delayed engagement, or ATF leaks near the valve body, inspect the regulator bore for scoring or wear. Replacing the regulator along with the 0630532183: INDENTED RING is recommended.
Q: Can I install this pressure regulator without removing the transmission?
A: Yes, in most cases the valve body is accessible after draining the fluid and dropping the pan. However, you must also replace the 4656306145: PISTON and 0732042767: COMPRESSION SPRING if they show signs of fatigue.
Q: Is the 4657.120.005 compatible with the ZF WG211 transmission?
A: Absolutely. This OEM part is factory-specified for both the WG191 and WG211 series. Always cross-reference your transmission serial number to confirm.
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Phone: +86 158 2286 3467 |
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