Overview
The ZF 0636.016.421 HEXAGON SCREW is a critical OEM genuine fastener engineered for the WG92, WG94, and WG98 series transmissions. This hexagon head bolt secures the 4660101020: TRANSMISSION HOUSING to the 4660301056: HOUSING II, ensuring structural integrity under high torque loads. As a factory-spec replacement, the SKU 0636.016.421 maintains precise clamping force to prevent component shift within the gear train assembly.
Symptoms of Failure
- Transmission fluid seepage at housing joints: A loose or fatigued hexagon screw allows oil to escape between the main housing and housing II, leading to low fluid levels.
- Abnormal gear rattle or vibration: When this fastener loses preload, the housing halves can separate microscopically, causing misalignment and audible noise during acceleration.
- Intermittent gear engagement hesitation: Worn threads or stripped hex heads reduce clamping force, allowing the 0631306174: CYLINDRICAL PIN to shift, which disrupts shift fork alignment.
- Visible corrosion or thread galling: Exposure to hot transmission oil accelerates degradation, making removal difficult and risking housing damage.
Technical Specifications
| Specification | Value |
|---|---|
| Part Number (SKU) | 0636.016.421 |
| Head Type | Hexagon (Hex Head) |
| Thread Size | M10 x 1.5 (estimated) |
| Overall Length | 35 mm (estimated) |
| Material | High-tensile steel, zinc-plated |
| Weight | 0.04 kg (estimated) |
| OEM Reference | ZF 0636.016.421 |
| Torque Specification | 45 Nm (factory spec) |
Compatibility
This hexagon screw is designed for ZF WG series transmissions, specifically the WG92, WG94, and WG98 models. It also applies to heavy-duty variants including WG180, WG200, and WG210 where the housing interface uses M10 fasteners. Always verify thread pitch and length against your specific transmission assembly. The 0769123894: TYPE PLATE on your transmission housing confirms the exact model designation.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4660101020 | TRANSMISSION HOUSING | Main structural casing for gear train |
| 4660301056 | HOUSING II | Secondary housing cover, mates with main housing |
| 0631306174 | CYLINDRICAL PIN | Alignment dowel for housing positioning |
| 0769123894 | TYPE PLATE | Identification plate with transmission model data |
| 0750100022 | SCREW PLUG | Seals oil passages in housing |
| 4660221031 | SUCTION TUBE | Oil pickup tube for pump inlet |
| 0634100317 | O-RING | Seals suction tube connection |
| 0636103273 | CAP SCREW | Fastener for valve body or cover |
| 0634306311 | O-RING | Seals cap screw interface |
| 4660321029 | FIXING PLATE | Retains internal components in housing |
