Overview
The ZF 4644.131.023 FILLER NOZZLE is a precision-engineered fluid delivery component designed exclusively for the WG 180 series transmission. This OEM genuine part, identified by SKU 4644.131.023, serves as the critical interface for introducing transmission oil into the hydraulic circuit. Positioned directly on the upper casing of the gearbox, it channels lubricant from the fill port to the internal sump while preventing debris ingress. When paired with a robust TRANSMISSION HOUSING, this nozzle ensures consistent oil flow during maintenance and operation. Its integrated sealing geometry works in tandem with the HOUSING to maintain system pressure integrity.
Symptoms of Failure
- Transmission oil seepage at the fill port: A worn filler nozzle often causes slow, persistent leaks around the neck area, leading to low fluid levels and eventual gear slipping under load.
- Difficulty achieving proper fluid level readings: When the nozzle deforms or cracks, it disrupts the oil flow path, causing false dipstick readings and potential overfilling or underfilling.
- Contaminated transmission fluid: A degraded seal allows dirt and moisture to bypass the O-RING, resulting in gritty or milky oil that accelerates internal wear.
- Whining noise during gear engagement: Insufficient lubrication from a faulty nozzle creates cavitation in the hydraulic system, producing audible whining sounds from the transmission housing.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 4644.131.023 |
| Material | Die-cast aluminum alloy with nitrile seal |
| Overall Length | 85 mm |
| Thread Size | M22 x 1.5 |
| Weight | 0.12 kg |
| OEM Reference | ZF 4644.131.023 |
| Operating Temperature Range | -40°C to +120°C |
Compatibility
This filler nozzle is engineered for the ZF WG 180 series, but its mounting pattern also fits the WG 200 and WG 150 variants when used with the correct THREADED BUSH. It is a direct replacement for earlier revisions in the WG 180 family, including models with serial numbers starting from 2015. Always verify the TYPE PLATE on your transmission to confirm compatibility. The nozzle integrates with the SHIFT SYSTEM and requires a COVER PLATE for full assembly. For secure mounting, use the GROOVED STUD provided in the kit.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644101080 | TRANSMISSION HOUSING | Main structural casing for gear assembly |
| 4644301333 | HOUSING | Secondary housing for valve body |
| 0730365125 | TYPE PLATE | Identification plate with serial number |
| 0631311009 | GROOVED STUD | Threaded fastener for nozzle mounting |
| 0636305019 | SCREW PLUG | Seals unused fill port openings |
| 4644301247 | THREADED BUSH | Adapter for alternate nozzle sizes |
| 0634303485 | O-RING | Seals nozzle-to-housing interface |
| 4644106055 | SHIFT SYSTEM | Hydraulic valve actuation assembly |
| 4642306050 | COVER PLATE | Protective plate over shift mechanism |
| 4644306464 | GASKET | Prevents fluid leaks between mating surfaces |
