Overview
The ZF 0636.420.072 COUNTERSUNK SCREW is a critical OEM fastening element engineered for the WG100, WG130, and WG131 transmission series. This countersunk screw secures internal housing components, ensuring precise alignment and clamping force within the gear train assembly. As an original ZF part (SKU: 0636.420.072), it prevents relative movement between the TRANSMISSION HOUSING and adjacent structural elements. Without this fastener, the transmission’s internal clearances would shift, leading to accelerated wear on bearings and shafts. It is categorized under Springs & Fasteners and is essential for maintaining the integrity of the entire power flow path.
Symptoms of Failure
- Transmission oil seepage at housing joints: A loose or fatigued countersunk screw compromises the seal between the HOUSING sections, allowing ATF to weep past gaskets.
- Audible metallic clicking during gear engagement: When this screw loses torque, internal components shift slightly, creating a distinct “click” under load—a classic sign of fastener failure in WG series units.
- Progressive gear slippage under heavy torque: The countersunk screw holds the HOUSING halves together; failure here causes misalignment of clutch packs, resulting in intermittent slipping.
- Vibration at specific RPM ranges: A worn screw allows the COVER to micro-move, creating harmonic vibrations that worsen over time.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 0636.420.072 |
| Type | Countersunk Screw (DIN 7991 / ISO 10642) |
| Thread Size | M8 x 1.25 (estimated) |
| Length | 25 mm (estimated) |
| Head Style | Flat 90° countersunk |
| Material | High-tensile steel, zinc-plated |
| Weight | ~12 grams |
| OEM Reference | ZF 0636.420.072 |
| Drive Type | Hex socket (Allen key) |
Compatibility
This OEM screw is specifically designed for ZF WG100, WG130, and WG131 transmissions. It also fits select variants of the WG180 and WG200 series where the countersunk fastener pattern matches. Always verify thread pitch and length against your specific housing assembly. The screw interfaces directly with the TRANSMISSION HOUSING and is often replaced alongside the GASKET to ensure a leak-free joint.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 2094101012 | TRANSMISSION HOUSING | Main structural casing for gear sets |
| 2094301036 | HOUSING | Intermediate housing section |
| 2094298057 | HOUSING | Rear housing component |
| 2094301071 | COVER | Access cover for valve body |
| 0750111371 | SHAFT SEAL | Prevents oil leakage at rotating shafts |
| 0634303085 | O-RING | Static seal between housing faces |
| 2094301030 | GASKET | Paper gasket for housing joint |
| 0631306670 | CYLINDRICAL PIN | Alignment dowel for housing |
| 0636011356 | HEXAGON SCREW | Standard hex head fastener |
| 4475280060 | SCREW PLUG | Seals threaded oil passages |
