Overview
The ZF 4642.301.180 UNION SCREW is a precision-engineered hydraulic connector designed for the valve body and oil circuit assemblies within the WG150, WG180, and WG201 transmission series. This OEM genuine part, identified by SKU 4642.301.180, functions as a critical sealing and flow-control point, directing pressurized transmission fluid to the clutch packs and torque converter. It sits at the interface between the main control unit and the 4642101109: TRANSMISSION HOUSING, ensuring that hydraulic pressure is maintained without cross-leakage. Without this union screw, the transmission cannot build the necessary line pressure for smooth gear engagement.
Symptoms of Failure
- External hydraulic fluid seepage at the valve body joint: A worn or cracked union screw allows ATF to escape, leaving visible drips on the bell housing or under the vehicle. This is a common long-tail search query for “ZF WG180 oil leak at valve body.”
- Erratic or delayed gear engagement: When the union screw loses its sealing integrity, pressure drops cause the transmission to hesitate when shifting from Park to Drive or Reverse.
- Whining or buzzing noise from the transmission pump: A failing union screw can introduce air into the hydraulic circuit, causing cavitation and audible pump noise during acceleration.
- Overheating transmission fluid: Insufficient pressure due to a compromised union screw reduces lubrication flow, leading to elevated operating temperatures and potential damage to the 4642301205: TRANSMISSION HOUSING.
Technical Specifications
| Specification | Detail |
|---|---|
| Part Number | 4642.301.180 |
| Material | High-strength alloy steel with zinc-nickel plating |
| Thread Size | M18 x 1.5 (estimated) |
| Overall Length | 42 mm |
| Hex Head Size | 22 mm |
| Sealing Method | Integrated O-ring groove (O-ring not included) |
| Weight | 0.065 kg |
| OEM Reference | ZF 4642.301.180 |
Compatibility
This union screw is specifically engineered for the ZF WG150, WG180, and WG201 series transmissions. It is a direct replacement for the original factory component in models such as the WG180-2, WG200-2, and WG201-2. The part also fits certain variants of the WG160 series where the valve body uses a M18 port. Always verify the thread pitch and sealing surface condition of the 0730365125: TYPE PLATE before installation to ensure correct identification of your transmission model. For additional mounting security, the 0631311009: GROOVED STUD is often replaced simultaneously during a valve body overhaul.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4642101109 | TRANSMISSION HOUSING | Main structural casing for gear and shaft assembly |
| 4642301205 | TRANSMISSION HOUSING | Rear housing section for WG180 series |
| 0730365125 | TYPE PLATE | Identification plate with transmission serial number |
| 0631311009 | GROOVED STUD | Alignment and fastening stud for valve body |
| 4642301168 | SCREEN SHEET | Fine mesh filter for hydraulic oil circuit |
| 4642301169 | SCREEN SHEET | Secondary filter screen for sump return |
| 0636100621 | HEXAGON SCREW | Fastener for transmission pan or cover |
| 4642301186 | SCREEN SHEET | High-flow filter element for WG201 |
| 4644106324 | SHIFT SYSTEM | Complete shift rail and fork assembly |
| 4644306598 | PLATE | Clutch piston retaining plate |
