Overview
The ZF 4139.320.008 GUIDE PIN is a precision-engineered alignment component specifically designed for the WG200 series transmission. This OEM genuine part ensures accurate positioning of the valve body and clutch housing assemblies during installation and operation. Located within the transmission’s hydraulic control system, the guide pin prevents misalignment that can lead to improper fluid flow and gear engagement. The SKU 4139.320.008 is manufactured to ZF’s exacting tolerances, guaranteeing a secure fit and long service life in heavy-duty commercial vehicle transmissions.
Symptoms of Failure
When the 4139.320.008 GUIDE PIN wears out, operators may notice several distinct failure indicators. Transmission oil leaks around the valve body often occur as the pin loses its sealing capability, allowing hydraulic fluid to escape. Intermittent gear slipping under load is another common symptom, as misaligned components fail to maintain proper clutch pressure. Delayed or harsh shifting between gears can develop when the guide pin’s surface becomes scored or deformed. Additionally, unusual metallic rattling noises from the transmission housing may indicate the pin has loosened, causing vibration against adjacent parts like the TRANSMISSION HOUSING.
Technical Specifications
| Specification | Value |
|---|---|
| Part Number | 4139.320.008 |
| Material | Hardened alloy steel (C45E) |
| Diameter | 12.0 mm (0.472 in) |
| Length | 38.5 mm (1.516 in) |
| Weight | 0.035 kg (0.077 lbs) |
| OEM Reference | ZF 4139.320.008 |
| Surface Finish | Zinc-plated, corrosion-resistant |
| Hardness | HRC 45-50 |
Compatibility
This guide pin is primarily engineered for the ZF WG200 series transmissions, including models such as WG180, WG200, and WG210. It also fits select variants of the ZF Ecomat 4HP and ZF 6HP series used in municipal buses and construction vehicles. For proper installation, ensure the pin is paired with a compatible TRANSMISSION HOUSING and the GROOVED STUD that secures the assembly. Always verify the TYPE PLATE on your transmission to confirm model-specific fitment before ordering.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644101216 | TRANSMISSION HOUSING | Main structural casing for gear assembly |
| 4644301223 | TRANSMISSION HOUSING | Alternate housing variant for WG200 |
| 0730365067 | TYPE PLATE | Identification plate for transmission model |
| 0631311009 | GROOVED STUD | Secures guide pin and valve body |
| 4644303060 | COVER PLATE | Protects internal components from debris |
| 4644303061 | COVER PLATE | Alternate cover plate for different housing |
| 0634306525 | O-RING | Seals fluid passages around guide pin |
| 0636305026 | SCREW PLUG | Closes hydraulic test ports |
| 4644301279 | SCREEN SHEET | Filters transmission fluid contaminants |
| 4644301088 | SEALING CAP | Prevents debris entry into housing |
