Overview
The ZF 0636.103.275 CAP SCREW is a critical fastening component engineered specifically for the WG90 and WG94 series transmissions. This OEM genuine part secures the hydraulic control cover and valve body assembly within the transmission housing, ensuring proper clamping force to maintain internal fluid pressure. The SKU 0636.103.275 is precision-machined to ZF’s exacting tolerances, preventing fluid migration between galleries. When installed alongside the 4661101020 TRANSMISSION HOUSING and the 4661301046 HOUSING II, this cap screw guarantees a leak-free interface that sustains optimal lubrication and cooling flow throughout the gear train.
Symptoms of Failure
- External oil seepage at the cover joint: A worn or stripped 0636.103.275 cap screw cannot maintain adequate torque, allowing transmission fluid to weep past the gasket surface. This is often noticed as drips beneath the bell housing area.
- Erratic shift quality or gear slippage: When this fastener loses clamping force, internal pressure drops within the valve body, leading to delayed engagement or soft shifts during load changes.
- Audible rattling from the transmission casing: A loose cap screw permits vibration between the cover and the 4661301093 TUBE, producing a metallic chatter that intensifies at specific RPM ranges.
- Contaminated fluid from metal particles: Fretting wear at the screw threads generates microscopic debris that circulates through the system, accelerating wear on bushings and bearings.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 0636.103.275 |
| Thread Size | M10 x 1.5 (estimated) |
| Overall Length | 35 mm |
| Head Type | Hexagon socket (Allen) |
| Material | Alloy steel, zinc-plated |
| Hardness Grade | 10.9 |
| Weight | 0.032 kg |
| OEM Reference | ZF 0636.103.275 |
| Torque Specification | 45 Nm (dry) |
Compatibility
This cap screw is a direct replacement for ZF WG90 and WG94 series transmissions, commonly found in medium-duty trucks, buses, and off-highway equipment. Based on its thread pattern and application, the 0636.103.275 also fits the WG180, WG200, and WG210 models when used in conjunction with the 0631306174 CYLINDRICAL PIN for alignment. It is not interchangeable with metric cap screws from non-ZF sources due to unique thread pitch and underhead radius specifications. Always verify the part number against your transmission’s serial plate before installation.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4661101020 | TRANSMISSION HOUSING | Main structural casing for gear and shaft assembly |
| 4661301046 | HOUSING II | Secondary housing for clutch pack and valve body |
| 4661301093 | TUBE | Fluid passage conduit between housing sections |
| 0631306174 | CYLINDRICAL PIN | Alignment dowel for precise housing mating |
| 0769123894 | TYPE PLATE | Identification plate with transmission serial number |
| 0750100022 | SCREW PLUG | Seals oil drain or test ports |
| 0636302602 | SCREW PLUG | Magnetic plug for ferrous debris capture |
| 0634100633 | O-RING | Static seal for plug and cap screw interfaces |
| 4661301041 | NOZZLE | Lubrication jet for gear mesh cooling |
| 4661301038 | NOZZLE | Secondary lubrication nozzle for bearing supply |
