Overview
The ZF 4644.121.212 OIL PIPE is a critical hydraulic conduit engineered specifically for the WG180 and WG200 transmission series. This OEM genuine part ensures precise lubrication and cooling oil flow within the valve body and clutch pack assembly. Positioned between the TRANSMISSION HOUSING and the rotating clutch drums, the 4644.121.212 oil pipe maintains consistent hydraulic pressure for smooth gear engagement. Without this component, the transmission cannot deliver the required oil volume to critical friction surfaces, leading to thermal stress and premature wear. The SKU 4644.121.212 is factory-machined to exact ZF tolerances, guaranteeing a leak-free seal in high-pressure applications.
Symptoms of Failure
- Hydraulic oil leaks near the valve body: A cracked or corroded 4644.121.212 oil pipe will drip transmission fluid, often pooling beneath the WG180 or WG200 housing.
- Delayed or harsh gear engagement: Insufficient oil flow from a blocked pipe causes clutch packs to engage late, producing a noticeable “clunk” when shifting from neutral to drive.
- Overheating transmission during operation: When the oil pipe fails to deliver cooling fluid, internal temperatures rise rapidly, triggering warning lights or thermal shutdown.
- Intermittent gear slipping under load: A partially obstructed 4644.121.212 pipe starves the torque converter, causing the transmission to lose power on inclines or during heavy hauling.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 4644.121.212 |
| Material | Seamless steel tube with zinc-nickel coating |
| Length | 215 mm (estimated) |
| Outer Diameter | 12 mm |
| Wall Thickness | 1.5 mm |
| Weight | 0.18 kg |
| OEM Reference | ZF 4644.121.212 |
| Seal Type | O-ring groove at both ends |
Compatibility
This oil pipe is designed for ZF WG180 and WG200 series transmissions used in heavy-duty commercial vehicles, agricultural tractors, and construction equipment. It directly interfaces with the DISCONNECTION valve assembly and the OUTPUT FLANGE oil gallery. The 4644.121.212 also mounts securely using HEXAGON SCREW fasteners to the TRANSMISSION HOUSING. Compatible models include WG180-1, WG180-2, WG200-1, and WG200-2 variants. Always verify your transmission serial number before ordering.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644105413 | DISCONNECTION | Isolates hydraulic circuits during clutch pack replacement |
| 4642303093 | OUTPUT FLANGE | Transfers torque from transmission to driveshaft |
| 0636021010 | HEXAGON SCREW | Secures oil pipe and housing components |
| 4644101222 | TRANSMISSION HOUSING | Main structural casing for gear train |
| 4644301226 | TRANSMISSION HOUSING | Alternate housing variant for WG200 |
| 0730365067 | TYPE PLATE | Identification tag with transmission specs |
| 0631311009 | GROOVED STUD | Alignment pin for housing assembly |
| 4644301298 | COVER PLATE | Seals access port on transmission housing |
| 0634306525 | O-RING | Hydraulic seal for oil pipe connections |
| 0636305026 | SCREW PLUG | Closes unused oil ports in valve body |
