Overview
The ZF 4644.131.051 FILLER NOZZLE is a precision-engineered fluid delivery component designed specifically for the WG 201 series transmission architecture. This OEM genuine part serves as the primary interface for introducing transmission fluid into the hydraulic circuit, ensuring correct fill levels during maintenance or rebuild operations. The nozzle integrates directly into the upper housing assembly, directing oil flow to the sump while preventing aeration. The SKU 4644.131.051 is manufactured to ZF’s exacting tolerances, guaranteeing a secure seal and consistent flow rate. When paired with a robust TRANSMISSION HOUSING, this filler nozzle maintains system integrity under high-pressure conditions.
Symptoms of Failure
- Transmission fluid leaking from the fill port area – A worn or cracked filler nozzle allows oil to seep past the sealing surface, often leaving puddles under the vehicle after extended operation.
- Hard shifting or delayed engagement – Insufficient fluid volume due to nozzle degradation leads to low hydraulic pressure, causing gear engagement hesitation and rough shifts.
- Overheating transmission – A compromised nozzle permits air ingress, aerating the fluid and reducing its cooling capacity, which triggers thermal warnings.
- Erratic fluid level readings – A damaged filler nozzle can cause false low-level alerts, as the dipstick or sensor receives inconsistent fluid feedback.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 4644.131.051 |
| Material | Die-cast aluminum with nitrile sealing surface |
| Weight | 0.18 kg (0.40 lbs) |
| Length | 95 mm |
| Thread Size | M22 x 1.5 |
| OEM Reference | ZF 4644.131.051 |
| Operating Temperature Range | -40°C to +120°C |
Compatibility
This filler nozzle is engineered for the ZF WG 201 series, including the WG180, WG200, and WG210 variants. It also fits select WG 211 and WG 220 models produced after 2015. The nozzle interfaces directly with the TRANSMISSION HOUSING and requires a THREADED BUSH for proper alignment. For sealing, pair it with a SCREW PLUG to prevent contamination during service intervals.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644101203 | TRANSMISSION HOUSING | Encloses gear train and hydraulic components |
| 4644301382 | TRANSMISSION HOUSING | Alternate housing variant for WG200 series |
| 4644301189 | THREADED BUSH | Provides threaded interface for nozzle installation |
| 0636302005 | SCREW PLUG | Seals fill port during non-service periods |
| 0634306198 | O-RING | Prevents fluid bypass at nozzle joint |
| 0634801098 | SEALING RING | Secondary seal for high-pressure zones |
| 0730365067 | TYPE PLATE | Identifies transmission model and serial number |
| 0631311009 | GROOVED STUD | Secures housing alignment during assembly |
| 4644301161 | COVER PLATE | Protects internal components from debris |
| 0636100621 | HEXAGON SCREW | Fastens cover plate to housing |
