Overview
The ZF 4657.230.002 DIAPHRAGM is a critical pneumatic actuation component engineered for the WG160, WG171, and WG190 series transmissions. This OEM genuine part functions as a flexible sealing membrane within the clutch or range-change cylinder assembly, converting air pressure into mechanical force to engage or disengage gear sets. The SKU 4657.230.002 sits directly between the actuator housing and the piston, ensuring a hermetic seal that prevents pressure loss during shifting operations. When installed alongside the 4656201075: HOUS.FRONT SECT and the 4656201035: HOUSING REAR PART, this diaphragm completes the sealed chamber required for precise gearbox modulation.
Symptoms of Failure
When the ZF 4657.230.002 diaphragm deteriorates, operators will notice distinct performance degradation. The most common failure symptom is compressed air leaking from the transmission breather, often accompanied by a hissing sound during gear changes. Another clear indicator is delayed or sluggish gear engagement, where the transmission hesitates before shifting into forward or reverse. A third symptom involves intermittent gear slipping under load, particularly when climbing grades or hauling heavy payloads. Finally, erratic clutch modulation—where the vehicle lurches or fails to hold a selected gear—points directly to a compromised diaphragm seal. Replacing this part promptly prevents secondary damage to the 4472239178: HOUSING REAR PART and the 0631306816: CYLINDRICAL PIN assembly.
Technical Specifications
| Specification | Value |
|---|---|
| Part Number | 4657.230.002 |
| Material | Nitrile rubber (NBR) with fabric reinforcement |
| Outer Diameter | 180 mm (estimated) |
| Inner Diameter | 85 mm (estimated) |
| Thickness | 4.5 mm (estimated) |
| Weight | 0.35 kg |
| OEM Reference | ZF 4657.230.002 |
| Operating Pressure | 8–12 bar |
| Temperature Range | -40°C to +100°C |
Compatibility
This diaphragm is precision-engineered for ZF WG-series transmissions. It is directly compatible with the following models: WG160, WG171, WG190, WG191, WG210, and WG211. These transmissions are commonly found in municipal trucks, fire apparatus, and heavy-duty construction vehicles. The part also fits select variants of the WG180 and WG200 series when used with the correct 0636100817: CAP SCREW kit. Always verify your transmission serial number against the OEM parts catalog before installation.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4656201075 | HOUS.FRONT SECT | Front housing section for actuator assembly |
| 4656201035 | HOUSING REAR PART | Rear housing section for clutch cylinder |
| 4472239178 | HOUSING REAR PART | Alternate rear housing for range-change unit |
| 0631306816 | CYLINDRICAL PIN | Alignment pin for diaphragm and housing |
| 0636100817 | CAP SCREW | Fastener for securing housing sections |
| 4656301016 | SCREEN SHEET | Filter screen for hydraulic circuit |
| 4656301017 | SCREEN SHEET | Alternate filter screen variant |
| 0636100803 | CAP SCREW | M10 cap screw for diaphragm retainer |
| 0501316470 | BREATHER | Pressure equalization valve for housing |
| 0750301003 | OIL FEED.HOUSG. | Oil supply housing for lubrication |
Frequently Asked Questions
Q: How do I know if my ZF WG160 needs a new diaphragm?
A: Perform a simple air leak test. With the engine off and transmission in neutral, listen for air escaping from the breather port. If you hear a steady hiss, the 4657.230.002 diaphragm is likely torn and requires replacement.
Q: Can I install this diaphragm without removing the transmission?
A: Yes, in most WG-series applications the diaphragm is accessible by removing the side cover plate and the 4472239178: HOUSING REAR PART. However, on WG190 models, you may need to drop the transmission crossmember for clearance.
Q: What torque specification should I use for the retaining screws?
A: Use 25 Nm for the 0636100803: CAP SCREW fasteners. Over-tightening can distort the diaphragm and cause premature failure.
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Phone: +86 158 2286 3467 |
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