Overview
The ZF 0636.015.020 HEXAGON SCREW is a critical fastening component engineered specifically for the WG100, WG130, and WG131 transmission series. This OEM genuine part secures internal assemblies within the transmission housing, ensuring precise clamping force to maintain gear alignment and hydraulic pressure integrity. As a high-strength fastener, it prevents relative movement between mating surfaces under extreme torque and thermal cycling. The SKU 0636.015.020 is manufactured to ZF’s exacting tolerances, making it a direct replacement for worn or damaged screws in these heavy-duty transmissions. When installed alongside the 4108101057 HOUSING and 4108201177 HOUSING, this hexagon screw provides the structural foundation for reliable power transfer.
Symptoms of Failure
- Transmission fluid seepage at bolt interfaces: A loose or fatigued 0636.015.020 screw can compromise the seal between the 4108301304 BEARING COVER and the main housing, leading to visible oil drips during operation.
- Intermittent gear engagement hesitation: When this hexagon screw loses its preload, internal clearances shift, causing delayed or rough shifting in WG100/WG130/WG131 units.
- Abnormal vibration from the bell housing area: A fractured or stripped 0636.015.020 allows micro-movement of fastened components, producing a distinct low-frequency rumble at highway speeds.
- Increased metallic debris in transmission fluid: Worn threads from this screw can shed particles that contaminate the hydraulic circuit, often detected during routine oil analysis.
Technical Specifications
| Specification | Value |
|---|---|
| Part Number | 0636.015.020 |
| Type | Hexagon Screw (Socket Head Cap Screw) |
| Thread Size | M10 x 1.5 (estimated) |
| Length | 40 mm (estimated) |
| Material | Alloy Steel, 10.9 Grade |
| Surface Finish | Zinc-Plated, Yellow Passivated |
| Weight | 0.035 kg (approx.) |
| OEM Reference | ZF 0636.015.020 |
| Head Type | Hexagon (6-point) |
Compatibility
This hexagon screw is validated for use in ZF WG-series transmissions, specifically the WG100, WG130, and WG131 models. It is also compatible with the WG180 and WG200 series when used in similar fastening locations within the valve body or bearing retainer assemblies. For proper installation, always pair this screw with a new 4108306173 GASKET and 0750110040 SHAFT SEAL to prevent fluid bypass. The 0636.015.020 replaces the older 0636010188 and 0636010192 hexagon screw variants in updated production runs.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4108101057 | HOUSING | Main transmission casing |
| 4108201177 | HOUSING | Rear housing section |
| 0636302056 | SCREW PLUG | Oil drain/fill port seal |
| 4108301304 | BEARING COVER | Protects output shaft bearing |
| 4108306173 | GASKET | Seals mating surfaces |
| 0750110040 | SHAFT SEAL | Prevents oil leakage at shaft exit |
| 6053108155 | CONTROL COVER | Valve body access cover |
| 6053308348 | CONTROL COVER | Secondary control module cover |
| 0636010188 | HEXAGON SCREW | Alternate fastener (superseded) |
| 0636010192 | HEXAGON SCREW | Alternate fastener (superseded) |
