Overview
The ZF 4646.131.401 FILLER NOZZLE is a precision-engineered OEM sub-assembly designed for the WG 250, WG 260, and WG 310 series transmissions. This component serves as the primary fluid entry point, directing transmission oil into the main housing during service or refill operations. Positioned on the upper section of the transmission assembly, the filler nozzle ensures a secure, leak-free seal between the external fill port and the internal oil gallery. The SKU 4646.131.401 is a direct replacement for worn or damaged units, restoring proper fluid flow and preventing contamination ingress. When replacing this nozzle, it is common to also inspect the TRANSMISSION HOUSING for cracks or wear, as the nozzle seats directly into this component.
Symptoms of Failure
- Visible oil seepage around the fill port: A degraded filler nozzle often causes slow, persistent oil leaks near the top of the transmission, leaving dark stains on the housing exterior.
- Difficulty achieving proper fluid level: If the nozzle is cracked or warped, air may enter the system during filling, leading to inaccurate dipstick readings and potential gear slipping under load.
- Contaminated transmission fluid: A failed seal allows dirt and moisture to bypass the nozzle, resulting in gritty or milky oil that accelerates internal wear.
- Whining or chattering from the gear train: Insufficient oil volume due to a leaking nozzle can cause intermittent lubrication failure, producing audible noise during shifting.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 4646.131.401 |
| Material | Reinforced Nylon / Aluminum Alloy |
| Overall Length | 85 mm (estimated) |
| Thread Size | M22 x 1.5 (estimated) |
| Weight | 0.12 kg (0.26 lbs) |
| OEM Reference | ZF 4646.131.401 |
| Seal Type | Integrated O-ring (NBR) |
Compatibility
This filler nozzle is engineered for the ZF WG series of powershift transmissions, specifically the WG 258, WG 260, WG 261, WG 308, WG 310, and WG 311 models. It also fits the WG 250 and WG 180 series when used with the appropriate HOUSING adapter. The part is not compatible with the WG 200 series without additional modification. During installation, always torque the HEXAGON SCREW and CAP SCREW to factory specifications to avoid distorting the nozzle flange.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4646101156 | TRANSMISSION HOUSING | Main structural casing that houses gears and shafts |
| 4646301327 | HOUSING | Secondary housing cover for valve body access |
| 0636015304 | HEXAGON SCREW | Fastener for securing filler nozzle bracket |
| 0636101828 | CAP SCREW | High-torque bolt for housing attachment |
| 4646301102 | COVER SHEET | Protective plate for internal oil passages |
| 4646301285 | COVER SHEET | Gasket-facing cover for sump access |
| 0730365190 | TYPE PLATE | Identification tag with serial number |
| 0631311009 | GROOVED STUD | Alignment pin for transmission assembly |
| 0636101193 | CAP SCREW | Fastener for clutch pack retention |
| 0636010179 | HEXAGON SCREW | Mounting screw for oil filter housing |
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