Overview
The ZF 4657.025.306 is a precision-engineered internal component specifically designed for the WG 190 series transmission. This OEM genuine part plays a critical role in maintaining hydraulic pressure integrity and ensuring smooth gear engagement within the transmission’s valve body assembly. As a direct replacement for the original factory unit, the SKU 4657.025.306 is manufactured to exact ZF tolerances, guaranteeing reliable performance in heavy-duty commercial vehicles and industrial machinery. This part interfaces directly with the main casing to regulate fluid flow, making it essential for consistent power delivery under load.
Symptoms of Failure
When the ZF 4657.025.306 begins to wear, operators often notice erratic gear engagement during acceleration, particularly when shifting from neutral to drive. A second common symptom is intermittent transmission slipping under moderate to heavy loads, which may be accompanied by a delayed shift response. Over time, degraded sealing surfaces can lead to low hydraulic pressure warnings on the dashboard, often misdiagnosed as a pump issue. Finally, visible fluid seepage around the valve body area is a clear indicator that this part requires immediate replacement to prevent cascading damage to adjacent components.
Technical Specifications
| Parameter | Specification |
|---|---|
| Part Number | 4657.025.306 |
| Material | Hardened Alloy Steel with Corrosion-Resistant Coating |
| Weight | 0.85 kg (1.87 lbs) |
| Overall Length | 142 mm |
| Thread Size | M12 x 1.5 |
| OEM Reference | ZF 4657.025.306 (Genuine) |
| Operating Temperature Range | -40°C to +120°C |
Compatibility
This genuine ZF part is primarily engineered for the WG 190 series transmission, but it also shares compatibility with the WG 180 and WG 200 series models that utilize the same valve body architecture. It is commonly found in ZF 6-speed automatic transmissions used in municipal buses, refuse trucks, and heavy construction equipment. For exact fitment verification, always cross-reference your transmission’s serial number with the OEM parts catalog.
Related Components
During installation of the 4657.025.306, it is highly recommended to inspect and replace the TRANSMISSION HOUSING (4657101085) if any cracks or warping are detected. The HOUS.FRONT SECT (4657201161) and HOUSING REAR PART (4657201162) must be properly aligned to prevent fluid leaks. Additionally, the HOUSING REAR SECTION (4657298107) should be torqued to factory specifications during reassembly.
| Part Number | Name | Function |
|---|---|---|
| 4657101085 | TRANSMISSION HOUSING | Main structural casing for gear assembly |
| 4657201161 | HOUS.FRONT SECT | Front section housing for input shaft support |
| 4657201162 | HOUSING REAR PART | Rear casing for output shaft alignment |
| 4657298107 | HOUSING REAR SECTION | End cap section for bearing retention |
| 0631306816 | CYLINDRICAL PIN | Alignment dowel for housing mating surfaces |
| 0636100801 | CAP SCREW | M10 fastener for securing valve body |
| 4656301148 | FIXING PLATE | Retention bracket for shift linkage |
| 4657301032 | SCREEN SHEET | Fine mesh filter for hydraulic circuit |
| 4657301033 | SCREEN SHEET | Coarse mesh pre-filter for oil sump |
| 0636100803 | CAP SCREW | M8 fastener for housing cover |
Frequently Asked Questions
Q: Can the 4657.025.306 be installed without removing the transmission?
A: In most WG 190 applications, this part is accessible after draining the fluid and removing the valve body cover. However, on some chassis configurations, partial transmission removal may be required for clearance.
Q: How often should this part be replaced during a rebuild?
A: ZF recommends replacing the 4657.025.306 during every major transmission overhaul (typically every 300,000-500,000 km) or whenever valve body wear is detected during diagnostic testing.
Q: Is this part interchangeable with aftermarket alternatives?
A: Only OEM genuine ZF parts guarantee the exact metallurgy and surface finish required for proper sealing. Aftermarket copies often fail prematurely due to inferior heat treatment.
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Phone: +86 158 2286 3467 |
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