Overview
The ZF 0636.020.237 HEXAGON SCREW is a critical fastening element engineered for the WG100, WG130, and WG131 transmission series. This OEM genuine part secures key housing assemblies within the gearbox, ensuring precise clamping force to maintain internal pressure tolerances. As a hexagon-headed bolt, it prevents loosening under high-vibration conditions common in industrial drivelines. The SKU 0636.020.237 is specifically designed to interface with adjacent components such as the 4143101009 HOUSING and the 4143301025 HOUSING, forming a sealed structural unit. Without this screw, the transmission cannot maintain its hydraulic circuit integrity.
Symptoms of Failure
- Hydraulic oil seepage around the housing joint: When the hexagon screw loses torque, the 0634313603 O-RING cannot compress properly, leading to visible drips under the bell housing.
- Intermittent gear engagement delay: A loose 0636.020.237 allows the housing to shift minutely, causing pressure drops that result in sluggish clutch pack application during shifts.
- Abnormal metallic rattling from the transmission casing: Vibration-induced loosening of this fastener creates clearance between the 4475280018 SCREW PLUG and the housing bore, producing a distinct chatter at idle.
- Progressive oil contamination from external debris ingress: A compromised seal at the screw interface permits dirt entry, accelerating wear on internal valve bodies.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 0636.020.237 |
| Head Type | Hexagon (Hex Head) |
| Thread Size | M10 x 1.5 (estimated) |
| Length | 35 mm (estimated) |
| Material | High-tensile steel, zinc-plated |
| Weight | 0.04 kg (approx.) |
| OEM Reference | ZF 0636.020.237 |
| Torque Specification | 45 Nm (factory spec) |
Compatibility
This hexagon screw is a direct fit for ZF WG100, WG130, and WG131 transmissions. It also applies to derivative models such as the WG180 and WG200 when used in conjunction with the 0501342341 SUPPORT RING for alignment. The fastener is compatible with both early and late production runs of these series. For complete sealing, pair it with the 4143298457 SEAL KIT and the 0634313591 O-RING. In high-torque applications, the 0636101068 CAP SCREW serves as an alternative for adjacent mounting points.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4143101009 | HOUSING | Main gearbox casing section |
| 4143301025 | HOUSING | Rear housing for output shaft |
| 0634313603 | O-RING | Seals screw-to-housing interface |
| 4475280018 | SCREW PLUG | Closes hydraulic test ports |
| 0501342341 | SUPPORT RING | Distributes clamping load |
| 4143298457 | SEAL KIT | Complete gasket set for overhaul |
| 0634313591 | O-RING | Secondary seal for valve body |
| 0636101068 | CAP SCREW | High-strength fastener for bell housing |
| 4143221013 | THROTTLE VALVE | Modulates shift pressure |
| 0634304484 | O-RING | Seals throttle valve bore |
