Overview
This genuine ZF 4166.339.268 SCREW PLUG is a critical sealing component engineered specifically for the WG 65 series transmission. Positioned within the transmission housing assembly, this OEM part ensures a leak-proof seal at fluid access points, preventing contamination and maintaining hydraulic pressure. The SKU 4166.339.268 is precision-machined to ZF’s exacting tolerances, making it an essential element for any rebuild or maintenance procedure involving the WG65 gearbox. When paired with a new 0636011038 HEXAGON SCREW and a fresh 0634313118 O-RING, this screw plug guarantees a secure, vibration-resistant seal that meets factory specifications.
Symptoms of Failure
When the ZF 4166.339.268 screw plug wears out or becomes damaged, operators may notice several distinct failure modes. Look for these specific long-tail symptoms to diagnose a failing plug:
- Oil seepage around the transmission drain or fill port: A compromised screw plug often leads to slow, persistent fluid leaks that leave visible residue on the 4616101059 TRANSMISSION HOUSING.
- Hydraulic pressure loss during heavy load operation: A worn plug cannot maintain proper sealing, causing gradual pressure drops that result in sluggish gear engagement or slipping.
- Contaminated transmission fluid: A loose or cracked screw plug allows dirt and moisture to enter the system, leading to accelerated wear on internal components like the 0732611049 FILTER INSERT.
- Visible thread stripping or corrosion: Over-torquing or age-related corrosion can deform the plug threads, making removal difficult and compromising the seal integrity.
Technical Specifications
| Part Number | 4166.339.268 |
| Product Type | Screw Plug (Drain/Fill Port) |
| Material | Steel, Zinc-Plated (Corrosion Resistant) |
| Thread Size | M26 x 1.5 (Estimated) |
| Overall Length | 18 mm (Estimated) |
| Head Type | Hexagon Socket (Allen Key Drive) |
| Weight | 0.04 kg (Approx.) |
| OEM Reference | ZF 4166.339.268 |
| Sealing Method | Requires 0634801152 SEALING RING or 0634303718 O-RING |
Compatibility
This genuine ZF screw plug is primarily designed for the WG 65 Series transmission, but it also fits several other ZF models that share the same port geometry. Compatible transmissions include the WG180, WG200, and WG250 series, as well as earlier WG120 and WG150 variants. For proper installation, always replace the plug in conjunction with the 0636011118 HEXAGON SCREW and the 0636016015 HEXAGON SCREW that secure adjacent housing covers. Use a 0631306085 CYLINDRICAL PIN to align the housing during reassembly.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4616101059 | TRANSMISSION HOUSING | Main structural casing for gear assembly |
| 0636011038 | HEXAGON SCREW | Fastener for housing cover |
| 0636011118 | HEXAGON SCREW | Fastener for valve body |
| 0636016015 | HEXAGON SCREW | Fastener for oil pan |
| 0631306085 | CYLINDRICAL PIN | Alignment dowel for housing |
| 0634313118 | O-RING | Seal for plug port |
| 0636304019 | SCREW PLUG | Alternate plug variant |
| 0634801152 | SEALING RING | Copper washer for plug |
| 0732611049 | FILTER INSERT | Oil filter element |
| 0634303718 | O-RING | Secondary seal for filter cover |
