Overview
This OEM genuine ZF diaphragm, part number 4657.330.004, is a critical pneumatic actuation component designed for the WG160, WG190, WG210, and WG230 series transmissions. It functions as a flexible sealing and pressure-responsive membrane within the transmission’s clutch or range-change actuator assembly. When pneumatic pressure is applied, the diaphragm deflects to engage or disengage specific gear sets, enabling smooth shifts under load. The SKU 4657.330.004 is manufactured to ZF’s exacting OE tolerances, ensuring a precise fit and reliable sealing against oil and air leakage. This part sits directly between the actuator housing and the piston, making it integral to the transmission’s hydraulic control logic.
Symptoms of Failure
- Erratic gear engagement or slipping: A cracked or stretched diaphragm cannot maintain proper pneumatic pressure, causing delayed or incomplete clutch engagement, especially under heavy torque.
- External oil or air leaks: Deterioration of the rubberized material leads to visible seepage around the actuator housing, often accompanied by a hissing sound during gear shifts.
- Harsh or delayed shifting: Loss of diaphragm elasticity results in inconsistent pressure modulation, producing jarring upshifts or a noticeable lag when moving between ranges.
- Increased transmission temperature: Continuous air loss forces the compressor to run longer, raising overall system heat and accelerating wear on adjacent seals.
Technical Specifications
| Parameter | Specification |
|---|---|
| Part Number (SKU) | 4657.330.004 |
| OEM Reference | ZF 4657.330.004 |
| Material | Nitrile rubber (NBR) with fabric reinforcement |
| Outer Diameter | ~180 mm (estimated) |
| Thickness | ~4.5 mm (estimated) |
| Weight | ~0.12 kg |
| Operating Pressure | 8–12 bar |
| Temperature Range | -40°C to +120°C |
Compatibility
This diaphragm is engineered for the ZF WG series of powershift transmissions. It is directly compatible with the WG160, WG190, WG210, and WG230 models. Based on its actuator design, it may also fit the WG180 and WG200 variants where the pneumatic actuator uses the same bolt pattern and stroke length. Always verify the actuator housing part numbers before installation—this diaphragm is commonly paired with the 4656101037: TRANSMISSION HOUSING, the 4656201075: HOUS.FRONT SECT, and the 4656201035: HOUSING REAR PART. For WG230 applications, the 4472239178: HOUSING REAR PART is also a common mating component.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4656101037 | TRANSMISSION HOUSING | Main structural casing that encloses the gear train and actuator assembly. |
| 4656201075 | HOUS.FRONT SECT | Forward section of the housing that aligns the input shaft and clutch pack. |
| 4656201035 | HOUSING REAR PART | Rear housing section supporting the output shaft and range-change actuator. |
| 4472239178 | HOUSING REAR PART | Alternate rear housing variant for WG230 series transmissions. |
| 0631306816 | CYLINDRICAL PIN | Precision alignment pin for doweling housing sections during assembly. |
| 4656301148 | FIXING PLATE | Retaining plate that secures the diaphragm and piston within the actuator bore. |
| 0636100817 | CAP SCREW | M10 fastener used to clamp the actuator cover to the housing. |
| 4656301016 | SCREEN SHEET | Fine-mesh filter screen for the pneumatic supply port (version A). |
| 4656301017 | SCREEN SHEET | Fine-mesh filter screen for the pneumatic supply port (version B). |
| 0636100803 | CAP SCREW | M8 fastener for securing the screen sheet and cover plate. |
Frequently Asked Questions
Q: How do I know if the 4657.330.004 diaphragm is failing?
A: The most common indicator is a gradual loss of pneumatic pressure, causing the transmission to hesitate or slip when shifting between forward and reverse ranges. You may also notice oil residue around the actuator vent port.
Q: Can I replace just the diaphragm without removing the transmission?
A: Yes, in most WG160/WG190 applications the diaphragm is accessible by removing the actuator cover. However, you must first drain the pneumatic system and carefully clean the mating surfaces. We recommend replacing the 4656301148: FIXING PLATE and 0636100817: CAP SCREW at the same time to ensure a leak-free seal.
Q: Is this diaphragm compatible with aftermarket actuator housings?
A: The 4657.330.004 is designed exclusively for OEM ZF housings. If you are using a non-OEM housing, verify the bolt circle diameter and piston stroke. For best results, always pair it with genuine ZF housings like the 4656201075: HOUS.FRONT SECT or 4656201035: HOUSING REAR PART.
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Phone: +86 158 2286 3467 |
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