Overview
The ZF 0631.501.453 FITTED KEY is a precision-machined locating component engineered specifically for the WG 65 Series transmission assembly. This OEM genuine part ensures correct rotational alignment between the gear shaft and its mating hub, preventing slippage under high-torque conditions. Positioned within the internal drivetrain of the WG65, the fitted key (SKU: 0631.501.453) acts as a positive mechanical lock that transfers torque without play. When installed alongside the 4616101059: TRANSMISSION HOUSING, it maintains the exact indexing required for synchronized gear engagement. The key is manufactured to ZF’s original tolerances, guaranteeing a tight fit that eliminates micro-movement during operation.
Symptoms of Failure
- Erratic gear engagement or “jumping out of gear”: A worn or sheared 0631.501.453 key allows the gear to shift axially, causing intermittent disengagement under load.
- Metallic clunking during acceleration: Backlash from a loose fitted key produces a distinct knocking sound as torque is applied, often mistaken for bearing failure.
- Oil contamination with metallic debris: As the key wears, fine steel particles enter the transmission fluid, visible during routine oil changes as a “glitter” effect.
- Vibration at specific RPM ranges: Loss of key integrity creates harmonic imbalance, particularly noticeable in the WG65 at cruising speeds between 1200-1800 RPM.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 0631.501.453 |
| Material | Case-hardened alloy steel (DIN 1.7131) |
| Length | 38.0 mm |
| Width | 12.0 mm |
| Height | 8.0 mm |
| Weight | 0.028 kg |
| OEM Reference | ZF 0631.501.453 |
| Surface Finish | Ground, deburred edges |
| Hardness | HRC 58-62 |
Compatibility
This fitted key is primarily designed for the ZF WG 65 Series transmission family. Based on its dimensional profile and spline interface, it is also compatible with the following ZF models that share the same gear shaft geometry: WG180, WG200, and WG250. For proper installation, always pair this key with the 0636011038: HEXAGON SCREW and 0636011118: HEXAGON SCREW to secure the retaining plate. Additionally, the 0636016015: HEXAGON SCREW is required for final torque locking. Verify your transmission’s serial number against ZF’s parts catalog before ordering.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4616101059 | TRANSMISSION HOUSING | Encloses and supports all internal gear assemblies |
| 0636011038 | HEXAGON SCREW | Secures the key retaining plate to the shaft |
| 0636011118 | HEXAGON SCREW | Fastens the gear hub to the shaft assembly |
| 0636016015 | HEXAGON SCREW | Provides final torque locking for the keyway |
| 0631306085 | CYLINDRICAL PIN | Aligns housing halves during reassembly |
| 0634313118 | O-RING | Seals the key access port against oil leakage |
| 0636304019 | SCREW PLUG | Closes the inspection hole on the housing |
| 0634801152 | SEALING RING | Prevents fluid bypass at the plug interface |
| 0732611049 | FILTER INSERT | Captures debris from worn keys before circulation |
| 0634303718 | O-RING | Gasket for the filter housing cover |
