Overview
The ZF 0631.511.020 WOODRUFF KEY is a precision-engineered locating key designed to secure rotating components—such as gears, pulleys, or clutches—to a shaft within ZF construction machinery transmissions. This OEM genuine part, identified by SKU 0631.511.020, fits into a milled slot on the shaft and a matching keyway in the hub, preventing relative rotation while allowing axial movement. In heavy-duty ZF transmissions like the WG series, this woodruff key ensures torque is transferred reliably from the input shaft to the gear train. When paired with a robust 4699101080: HOUSING and a sealed 0501329881: HOUSING COVER, the key maintains driveline integrity under high load cycles.
Symptoms of Failure
- Transmission gear slipping under load: A worn or sheared woodruff key allows the gear to rotate independently on the shaft, causing intermittent power loss or audible clunking during acceleration.
- Excessive backlash in the drivetrain: As the key degrades, the clearance between the shaft and hub increases, leading to noticeable play in the output shaft when shifting between forward and reverse.
- Metal debris in transmission oil: Fretting or fracture of the key produces fine metallic particles that contaminate the lubricant, often detected during routine oil analysis or when draining the sump.
- Vibration at specific RPM ranges: A loose key causes unbalanced rotation, generating harmonic vibrations that resonate through the transmission housing and into the chassis.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number (SKU) | 0631.511.020 |
| Type | Woodruff Key (Half-Moon Key) |
| Material | Case-Hardened Alloy Steel (DIN 6888) |
| Width (Nominal) | 8 mm |
| Height (Nominal) | 11 mm |
| Diameter (Radius) | 25 mm |
| Weight | Approx. 0.015 kg |
| OEM Reference | ZF 0631.511.020 |
| Hardness | HRC 48–52 |
Compatibility
This woodruff key is primarily used in ZF WG series transmissions commonly found in construction machinery, including wheel loaders, telehandlers, and graders. Compatible models include WG180, WG200, WG210, and WG240. It also appears in certain ZF Ecomat and Ecolife variants where a positive shaft-to-hub lock is required. For complete assembly integrity, always inspect the 0630513065: SNAP RING that retains the gear on the shaft and replace the 0634306309: O-RING on the housing cover to prevent lubricant ingress.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4699101080 | HOUSING | Encloses the gear train and supports shaft bearings |
| 0501329881 | HOUSING COVER | Seals the transmission housing and retains lubricant |
| 0630513065 | SNAP RING | Axially locks gears and bearings onto shafts |
| 0634306309 | O-RING | Provides static seal between housing and cover |
| 0637885612 | BREATHER | Equalizes internal pressure and vents moisture |
| 0501319149 | SCREW PLUG | Seals oil fill/drain ports in the housing |
| 0636302022 | SCREW PLUG | Magnetic plug for ferrous debris collection |
| 0634801038 | SEALING RING | Copper washer for high-pressure sealing under plugs |
| 0730365801 | TYPE PLATE | Identification plate with transmission serial number |
| 4699001080 | GK10 | Gasket kit containing seals and O-rings for overhaul |
