Overview
The ZF 4644.121.210 OIL PIPE is a precision-engineered fluid conduit specifically designed for the WG 201 series transmissions. This OEM genuine part ensures the correct routing of hydraulic oil to critical lubrication points within the gear train, maintaining optimal pressure and flow for clutch pack engagement and bearing cooling. As an integral component of the transmission’s internal lubrication circuit, the SKU 4644.121.210 directly supports the durability of adjacent assemblies, including the 4644101203: TRANSMISSION HOUSING and the 4644301382: TRANSMISSION HOUSING, by delivering a steady supply of filtered oil to high-wear zones.
Symptoms of Failure
When the ZF 4644.121.210 oil pipe degrades or becomes obstructed, operators may notice specific performance issues. Common failure indicators include:
- Visible oil seepage near the WG201 bell housing – Cracks or loose fittings in the pipe allow hydraulic fluid to escape, often pooling beneath the transmission.
- Delayed or harsh gear engagement – A compromised oil pipe reduces line pressure, causing clutches to slip or engage abruptly during shifts.
- Elevated transmission operating temperatures – Restricted oil flow through a damaged pipe starves the cooler circuit, leading to overheating under load.
- Whining or grinding noises from the gearbox – Insufficient lubrication due to a blocked pipe accelerates bearing wear, producing audible distress.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 4644.121.210 |
| OEM Reference | ZF 4644.121.210 |
| Material | Steel with anti-corrosion coating |
| Length (approx.) | 210 mm |
| Outer Diameter | 12 mm |
| Wall Thickness | 1.5 mm |
| Weight | 0.18 kg |
| Sealing Method | O-ring and sealing ring interface |
Compatibility
This oil pipe is engineered for the ZF WG 201 series, but its design also suits earlier WG180 and WG200 variants that share the same lubrication architecture. It is a direct replacement for transmissions originally equipped with the 4644301189: THREADED BUSH and 0636302005: SCREW PLUG in the oil gallery. Always verify the housing casting numbers—such as those on the 4644101203 or 4644301382 units—to confirm fitment before installation.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644101203 | TRANSMISSION HOUSING | Main structural casing for gear and clutch assembly |
| 4644301382 | TRANSMISSION HOUSING | Alternate housing variant for WG200/WG201 series |
| 4644301189 | THREADED BUSH | Provides threaded port for oil pipe connection |
| 0636302005 | SCREW PLUG | Seals unused oil gallery ports |
| 0634306198 | O-RING | Creates leak-proof seal at pipe junctions |
| 0634801098 | SEALING RING | Metal-to-metal seal for high-pressure oil circuits |
| 0730365067 | TYPE PLATE | Identification plate for transmission model verification |
| 0631311009 | GROOVED STUD | Alignment pin for housing and valve body positioning |
| 4644301161 | COVER PLATE | Protective cover over oil pipe access area |
| 0636100621 | HEXAGON SCREW | Fastener for securing oil pipe brackets |
