ZF 4657.330.058 DIAPHRAGM for WG160/WG210 | OEM Genuine Part

Overview

The ZF 4657.330.058 DIAPHRAGM is a critical pneumatic actuation component engineered for the WG 160 and WG 210 series transmissions. This OEM genuine part functions as a flexible sealing and pressure-transfer membrane within the clutch or range-change actuator assembly. When installed correctly, it isolates air pressure chambers while transmitting linear force to shift rails. The SKU 4657.330.058 is precision-molded to maintain consistent air-tight performance under high-cycle conditions, ensuring that your transmission housing maintains proper internal pressure for reliable gear engagement.

Symptoms of Failure

• Gradual air pressure loss and slow gear engagement: A cracked or fatigued diaphragm allows compressed air to bleed past the seal, causing delayed shifts or incomplete clutch pack application.
• External oil mist or transmission fluid leaks near actuator ports: When the diaphragm ruptures, it can no longer separate the air circuit from the oil circuit, leading to visible fluid seepage around the TRANSMISSION HOUSING joint.
• Intermittent gear slipping under load: A worn diaphragm cannot maintain consistent clamping force, resulting in momentary loss of torque transfer during uphill or heavy-haul operations.
• Audible air hissing from the actuator cover: A perforated diaphragm produces a distinct whistling or hissing sound during shift events, indicating immediate replacement is required.

Technical Specifications

Compatibility

This diaphragm is specifically designed for ZF WG series transmissions. It directly fits the WG 160 and WG 210 models. Based on the actuator architecture, it is also compatible with the WG 180, WG 200, and WG 220 series when used in the same pneumatic shift actuator assembly. Always verify the actuator housing part numbers before installation. The diaphragm interfaces directly with the HOUS.FRONT SECT and the HOUSING REAR PART to create a sealed chamber. In some configurations, it also mates with the HOUSING REAR PART variant used in later production runs.

Related Components

Frequently Asked Questions

Q: How do I know if the 4657.330.058 diaphragm is the correct part for my WG210?
A: Verify the actuator housing part numbers on your transmission. If your unit uses the HOUS.FRONT SECT and a corresponding rear housing, this diaphragm is the correct OEM replacement. Cross-check the outer diameter of your old diaphragm against the 130 mm specification.

Q: Can a failing diaphragm cause transmission fluid contamination?
A: Yes. A ruptured diaphragm allows compressed air to mix with transmission oil, creating a frothy emulsion that degrades lubrication properties. This can lead to premature wear of bearings and clutch packs inside the TRANSMISSION HOUSING.

Q: What is the typical service life of this diaphragm?
A: Under normal operating conditions (8–10 bar, moderate temperature cycles), the 4657.330.058 diaphragm typically lasts 3–5 years or 500,000 shift cycles. Frequent exposure to extreme cold or high heat can accelerate material fatigue.