Overview
The ZF 4657.230.006 DIAPHRAGM is a critical pneumatic actuation component engineered specifically for the WG 210 Series transmission. This OEM genuine part functions as a flexible sealing and pressure-transfer membrane within the shift actuator assembly, converting air pressure into precise mechanical movement for clutch and gear engagement. The SKU 4657.230.006 sits directly between the actuator housing and the piston, ensuring a hermetic seal that maintains consistent hydraulic or pneumatic force. Without this diaphragm, the transmission cannot modulate pressure correctly, leading to erratic shifting. It is frequently replaced alongside the TRANSMISSION HOUSING and the HOUS.FRONT SECT during a full actuator rebuild.
Symptoms of Failure
- Air or oil leaks near the shift actuator: A cracked or worn diaphragm allows pressurized fluid or compressed air to escape, often visible as wetness around the housing seam.
- Gear slipping under load: When the diaphragm loses elasticity, it cannot hold sufficient pressure to keep clutches engaged, causing the transmission to slip during acceleration or hill climbs.
- Delayed or harsh shifting: A failing diaphragm creates inconsistent pressure buildup, resulting in a noticeable lag between gear changes or abrupt engagement that jars the driveline.
- Erratic neutral-to-drive engagement: The vehicle may lurch forward or fail to engage immediately when shifting from neutral, indicating the diaphragm is not sealing properly against the HOUSING REAR PART.
Technical Specifications
| Part Number | 4657.230.006 |
| Material | Nitrile rubber (NBR) with fabric reinforcement |
| Outer Diameter | 230 mm |
| Thickness | 4.5 mm |
| Operating Pressure Range | 6–12 bar |
| Temperature Range | -40°C to +120°C |
| Weight | 0.18 kg |
| OEM Reference | ZF 4657.230.006 |
| Fastener Torque Spec | Use CAP SCREW (0636100801) at 25 Nm |
Compatibility
This diaphragm is designed for the WG 210 Series but also fits select models in the WG180, WG200, and WG250 families that share the same actuator architecture. It is a direct replacement for transmissions in ZF Ecomat and Ecolife platforms where the shift actuator uses a 230mm diaphragm. Always verify the actuator housing part number; if you are replacing the CYLINDRICAL PIN (0631306792) or the FIXING PLATE (4656301148), this diaphragm should be replaced simultaneously to ensure a proper seal.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4657101033 | TRANSMISSION HOUSING | Main structural casing for gear sets |
| 4657201027 | HOUS.FRONT SECT | Front section of the actuator housing |
| 4657201012 | HOUSING REAR PART | Rear section sealing the diaphragm |
| 0631306792 | CYLINDRICAL PIN | Alignment pin for housing assembly |
| 0636100801 | CAP SCREW | Fastener for diaphragm retention |
| 4656301148 | FIXING PLATE | Secures diaphragm to actuator |
| 4657301032 | SCREEN SHEET | Filter screen for oil intake |
| 4657301033 | SCREEN SHEET | Secondary filter screen |
| 0636100803 | CAP SCREW | Alternate fastener for housing |
| 4681301040 | OIL FEED.HOUSG. | Oil supply channel housing |
