ZF 0630.501.001 RETAINING RING for WG100/WG201 | OEM Genuine Part

Overview

The ZF 0630.501.001 RETAINING RING is a precision-engineered circlip designed to secure internal components within the clutch drum or planetary gear assembly of ZF WG 100 and WG 201 series transmissions. This OEM genuine part, identified by SKU 0630.501.001, provides axial retention for bearings, gears, and thrust washers, preventing unwanted movement under high torque loads. When installed correctly, it maintains critical clearances between the TRANSMISSION HOUSING (4644101160) and the rotating shaft assembly, ensuring consistent hydraulic pressure distribution across the clutch packs.

Symptoms of Failure

• Intermittent gear slippage under load: A worn or fatigued retaining ring can allow the clutch drum to shift axially, causing momentary loss of drive in forward or reverse gears.
• Metallic rattling from transmission sump: Broken ring fragments often circulate through the oil system, producing a distinct tapping noise during idle or low-speed operation.
• Sudden loss of reverse gear engagement: When the ring fails in the rear planetary assembly, the reverse clutch pack loses its preload, resulting in delayed or incomplete engagement.
• Oil contamination with steel particles: Abrasive wear on the ring groove generates fine metallic debris visible during oil changes, often accompanied by reduced hydraulic pressure.

Technical Specifications

Compatibility

This retaining ring is specifically engineered for the ZF WG 100 Series (including WG120, WG150, WG180) and WG 201 Series (WG200, WG210) transmissions. It is commonly used in the clutch drum assembly where it interfaces with the TRANSMISSION HOUSING (4644301323) and the THREADED BUSH (4644301189). For proper sealing, always replace the SCREW PLUG (4475280043) when servicing this ring. The part also fits select ZF Ecomat 4HP and 5HP models that share the same planetary carrier design.

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