Overview
The ZF 4475.280.052 SCREW PLUG is an OEM genuine sealing component engineered for the WG100, WG130, and WG131 transmission series. This precision-machined plug secures fluid passages within the valve body and housing assembly, preventing pressurized oil from escaping the hydraulic control circuit. The SKU 4475.280.052 is a direct-fit replacement that maintains factory-specified torque retention and sealing integrity. It is typically installed into the main housing bore, where it interfaces with the 4143101009: HOUSING and the 4143301025: HOUSING to create a leak-proof seal under high-pressure conditions.
Symptoms of Failure
- Oil seepage around the transmission pan or valve body: A worn or stripped screw plug allows hydraulic fluid to weep past the threads, leaving visible residue on the housing exterior.
- Erratic shift timing or delayed engagement: Loss of line pressure due to a compromised plug causes inconsistent clutch and band application, resulting in harsh or delayed gear changes.
- Low transmission fluid level without external pan damage: Internal leakage through a failed plug can reduce sump volume, triggering low-fluid warnings or overheating.
- Whining or buzzing noise from the transmission pump: Air ingestion through a loose plug creates cavitation, producing audible high-frequency sounds during operation.
Technical Specifications
| Parameter | Specification |
|---|---|
| Part Number | 4475.280.052 |
| Thread Size | M18 x 1.5 (estimated) |
| Overall Length | 22 mm |
| Head Diameter | 24 mm hex |
| Material | Carbon steel, zinc-plated |
| Weight | 0.04 kg |
| OEM Reference | ZF 4475.280.052 |
| Sealing Method | Integrated O-ring groove (requires 0634313603: O-RING) |
Compatibility
This screw plug is specifically validated for the following ZF transmission models: WG100, WG130, and WG131. It also fits select variants of the WG180 and WG200 series where the housing bore dimensions match. For applications using the 4475280018: SCREW PLUG in adjacent ports, verify thread pitch compatibility. Always replace the mating 0634313603: O-RING during installation to ensure proper sealing.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4143101009 | HOUSING | Main transmission case section |
| 4143301025 | HOUSING | Valve body housing cover |
| 0634313603 | O-RING | Seal for screw plug interface |
| 4475280018 | SCREW PLUG | Alternate plug for adjacent ports |
| 0501342341 | SUPPORT RING | Backup ring for O-ring groove |
| 4143298457 | SEAL KIT | Complete gasket and seal set |
| 0634313591 | O-RING | Secondary seal for housing joints |
| 0636101068 | CAP SCREW | Fastener for housing attachment |
| 4143221013 | THROTTLE VALVE | Pressure modulation valve |
| 0634304484 | O-RING | Seal for throttle valve bore |
