Overview
The ZF 4644.121.432 OIL PIPE is a critical fluid delivery component engineered specifically for the WG200 and WG201 transmission series. This OEM genuine part ensures precise lubrication and hydraulic pressure distribution within the gear train, directly supporting clutch pack engagement and planetary gear cooling. As a factory-specified conduit, the SKU 4644.121.432 routes transmission fluid from the valve body to the rotating drum assembly, maintaining consistent oil flow under high thermal loads. Its seamless integration with the 4644101175 TRANSMISSION HOUSING and 4644301221 TRANSMISSION HOUSING ensures leak-free operation in heavy-duty industrial applications.
Symptoms of Failure
- Transmission oil leaks at the pipe junction: A cracked or corroded 4644.121.432 oil pipe often causes visible fluid seepage around the housing mating surface, leading to low oil levels and eventual overheating.
- Delayed or harsh gear engagement: When this pipe becomes clogged or deformed, hydraulic pressure drops, resulting in sluggish shifting or abrupt clutch application during acceleration.
- Whining noise from the transmission pump: Restricted oil flow through a damaged pipe forces the pump to cavitate, producing a high-pitched whine that intensifies under load.
- Intermittent loss of drive in forward gears: A compromised oil pipe starves the clutch packs of fluid, causing sporadic slipping or complete loss of torque transmission in WG200/WG201 units.
Technical Specifications
| Part Number | 4644.121.432 |
| OEM Reference | ZF 4644.121.432 |
| Material | Seamless drawn steel with anti-corrosion coating |
| Length | 285 mm (estimated) |
| Outer Diameter | 12 mm |
| Wall Thickness | 1.5 mm |
| Weight | 0.18 kg |
| Sealing Method | Compression fit with O-ring groove |
Compatibility
This oil pipe is factory-designed for the ZF WG200 and WG201 series transmissions, commonly found in municipal trucks, construction loaders, and agricultural tractors. It also retrofits into select WG180 variants when used with the correct 0730365067 TYPE PLATE for model verification. For secure mounting, always pair this pipe with the 0631311009 GROOVED STUD to prevent vibration-induced loosening. Additional compatible housings include the WG150 series with minor adapter modifications.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644101175 | TRANSMISSION HOUSING | Main structural casing for gear assembly |
| 4644301221 | TRANSMISSION HOUSING | Alternate housing for WG201 variants |
| 0730365067 | TYPE PLATE | Identification tag for transmission model |
| 0631311009 | GROOVED STUD | Fastener for oil pipe retention |
| 4644303060 | COVER PLATE | Seals the oil pipe access port |
| 4644303061 | COVER PLATE | Alternative cover for different housing |
| 0634306525 | O-RING | Hydraulic seal for pipe connections |
| 0636305026 | SCREW PLUG | Closes unused oil passages |
| 0501316470 | BREATHER | Equalizes internal transmission pressure |
| 4644301279 | SCREEN SHEET | Filters debris from oil flow |
