Overview
The ZF 0636.100.729 HEXAGON SCREW is a critical fastening component engineered for the final drive assembly of ZF WG-series transmissions. This OEM genuine part secures the differential housing and crown wheel assembly, ensuring precise clamping force under high torque loads. Designed specifically for WG100, WG130, and WG131 models, the SKU 0636.100.729 replaces worn or stripped bolts to maintain gear alignment and prevent axial play. When paired with a CROWN WHEEL or DIFFERENTIAL assembly, this hexagon screw guarantees structural integrity during heavy-duty operation.
Symptoms of Failure
- Oil seepage around the differential housing: A loose or fatigued hexagon screw compromises the seal between the DIFFERENTIAL HOUSING and the transmission casing, leading to gradual lubricant loss.
- Gear whine or clunking during acceleration: Insufficient clamping force allows the DIFFERENTIAL to shift slightly, causing abnormal contact patterns on the crown wheel and pinion.
- Vibration in the driveline at highway speeds: A broken or stretched hexagon screw permits rotational imbalance in the differential assembly, transmitting harsh feedback through the chassis.
- Metal debris in transmission fluid: Sheared screw heads or stripped threads introduce ferrous particles that accelerate bearing wear in the final drive.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 0636.100.729 |
| Head Type | Hexagon (6-point socket) |
| Thread Size | M12 x 1.5 (estimated) |
| Length | 45 mm (estimated) |
| Material | High-tensile steel, zinc-plated |
| Weight | 0.045 kg (estimated) |
| OEM Reference | ZF 0636.100.729 |
| Torque Specification | 85 Nm + 90° (factory spec) |
Compatibility
This hexagon screw is validated for ZF WG100, WG130, and WG131 transmissions. It also fits WG180 and WG200 models when used in the differential mounting flange. Always verify thread pitch and length against your existing hardware. For complete differential rebuilds, consider the AXLE BEVEL GEAR and THRUST WASHER as companion parts.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 2098109042 | DIFFERENTIAL | Distributes torque between axles |
| 2098309011 | CROWN WHEEL | Transfers power to differential gears |
| 2099209001 | DIFFERENTIAL | Rear axle torque distribution |
| 2098309010 | DIFFERENTIAL HOUSING | Encloses differential gears |
| 2098309009 | DIFFERENTIAL HOUSING | Alternative housing variant |
| 2098309031 | AXLE BEVEL GEAR | Drives axle shaft rotation |
| 2098309030 | AXLE BEVEL GEAR | Left-side bevel gear |
| 2098309032 | DIFFERENTIAL BEVEL GEAR | Planetary gear in differential |
| 12883200682 | THRUST WASHER | Reduces axial friction |
| 0635332059 | BALL BEARING | Supports rotating shafts |
