Overview
The ZF 0636.104.901 HEX.SOCKET BUTTON HEAD SCREW is a critical OEM genuine fastener engineered for secure clamping within the WG100, WG130, and WG131 transmission assemblies. This precision-machined screw anchors the housing cover to the main gear case, ensuring zero movement under high-torque loads. As a genuine ZF part (SKU: 0636.104.901), it replaces worn or stripped fasteners that compromise the structural integrity of the drivetrain. When installed alongside the 4699101108: HOUSING and 4699102172: INPUT components, this button head screw maintains the precise alignment required for smooth power transfer.
Symptoms of Failure
- Oil seepage around housing bolts: A loose or fatigued 0636.104.901 screw allows transmission fluid to weep past the gasket, leaving visible residue on the bell housing.
- Gear engagement hesitation: When this fastener loses clamping force, the 4699001195: GK10LD clutch pack may shift slightly, causing delayed or rough gear changes.
- Vibration at steady speeds: A stripped hex socket or broken head creates micro-movement in the 4699103058: OUTPUT flange, transmitting vibration through the driveline.
- Torque converter shudder: In WG130 units, a failing button head screw can allow the input shaft to drift, producing a low-frequency shudder during lockup.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 0636.104.901 |
| Type | Hex Socket Button Head Screw |
| Thread Size | M8 x 1.25 (estimated) |
| Length | 25 mm (estimated) |
| Head Diameter | 14 mm (estimated) |
| Material | Alloy steel, 10.9 grade, zinc-plated |
| Weight | ~12 grams |
| OEM Reference | ZF 0636.104.901 |
| Hex Drive Size | 5 mm (estimated) |
Compatibility
This genuine ZF fastener is specifically designed for the WG100, WG130, and WG131 series transmissions. It also fits select WG180 and WG200 models where the housing cover uses M8 button head screws. Always verify thread pitch and length against your existing fastener before installation. The 0636.104.901 screw is commonly replaced during full rebuilds alongside the 4699105125: TURNTABLE BEARING and 0501329881: HOUSING COVER.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4699001195 | GK10LD | Clutch pack assembly |
| 4699101108 | HOUSING | Main gear case |
| 4699102172 | INPUT | Input shaft assembly |
| 4699103058 | OUTPUT | Output flange |
| 4699105125 | TURNTABLE BEARING | Rotary support bearing |
| 0501329881 | HOUSING COVER | Sealing cover plate |
| 0630513065 | SNAP RING | Retaining ring |
| 0634306309 | O-RING | Fluid seal |
| 0637885612 | BREATHER | Pressure equalization valve |
| 0769100082 | TYPE PLATE | Identification tag |
