Overview
The ZF 4644.121.490 OIL PIPE is a critical fluid delivery component engineered specifically for the WG 201 series transmission. This genuine OEM part ensures precise lubrication and hydraulic pressure flow within the valve body and rotating clutch assemblies. By maintaining consistent oil circulation, the 4644.121.490 prevents overheating and reduces friction on planetary gears. The SKU 4644.121.490 is machined from high-strength steel to withstand continuous thermal cycling and vibration. It connects directly to the 4644101160: TRANSMISSION HOUSING and interfaces with the 4644301323: TRANSMISSION HOUSING to form a sealed oil gallery. Without this pipe, the transmission cannot maintain proper line pressure, leading to immediate performance degradation.
Symptoms of Failure
- External oil seepage at pipe junctions – Cracks or corrosion on the 4644.121.490 cause visible ATF drips near the bell housing, often mistaken for a pan gasket leak.
- Delayed or harsh gear engagement – A compromised oil pipe reduces hydraulic pressure, resulting in sluggish shifts between 1st and 2nd gear under load.
- Transmission overheating warning – Insufficient oil flow through a blocked or deformed pipe leads to elevated sump temperatures, triggering dashboard alerts.
- Whining noise during acceleration – Air entrainment from a loose pipe connection creates a high-pitched sound that intensifies with RPM.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 4644.121.490 |
| Material | Seamless drawn steel, zinc-nickel plated |
| Overall Length | 215 mm ± 0.5 mm |
| Outer Diameter | 12 mm |
| Wall Thickness | 1.5 mm |
| Weight | 0.18 kg |
| OEM Reference | ZF 4644.121.490 |
| Sealing Surface | O-ring groove for 0634306198: O-RING |
Compatibility
This oil pipe is designed for ZF WG 201 series transmissions, including the WG180, WG200, and WG210 variants. It also fits select WG 150 models with identical oil gallery routing. The 4644.121.490 is not compatible with older WG 120 or WG 130 units without modifying the 4644301189: THREADED BUSH and 4475280043: SCREW PLUG assemblies. Always verify the transmission serial number against ZF parts catalog before installation.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644101160 | TRANSMISSION HOUSING | Main structural casing for gear train |
| 4644301323 | TRANSMISSION HOUSING | Rear housing with oil channel ports |
| 4644301189 | THREADED BUSH | Sealing insert for pipe retention |
| 4475280043 | SCREW PLUG | Oil gallery access closure |
| 0634306198 | O-RING | Hydraulic seal at pipe ends |
| 0730365067 | TYPE PLATE | Identification tag for transmission |
| 4644301161 | COVER PLATE | Protective shield over valve body |
| 0636100621 | HEXAGON SCREW | Fastener for housing attachment |
| 0631610020 | SET SCREW | Adjustable stop for shift linkage |
| 0501218540 | BREATHER | Pressure equalization vent |
