Overview
The ZF 4644.121.242 OIL PIPE is a precision-engineered fluid conduit designed specifically for the lubrication and cooling circuits within ZF WG180 and WG200 series transmissions. This OEM genuine part ensures that pressurized oil is delivered directly to critical bearing surfaces and gear meshes, preventing thermal degradation and mechanical wear. The SKU 4644.121.242 is a direct replacement component that interfaces seamlessly with the TRANSMISSION HOUSING (4644101208) and the HOUSING (4644301333) to maintain proper hydraulic circuit integrity. Without this pipe, the transmission cannot sustain adequate oil pressure for clutch pack engagement or bearing lubrication.
Symptoms of Failure
- External oil leaks at the pipe-to-housing interface: Cracks or fatigue in the 4644.121.242 pipe cause visible fluid drips, often mistaken for a failing O-RING (0634303485) seal.
- Intermittent gear slipping under load: Reduced oil flow due to a restricted or deformed pipe leads to insufficient clutch pack pressure, causing hesitation during upshifts.
- Elevated transmission operating temperature: A compromised oil pipe disrupts the cooling circuit, causing the fluid to overheat and degrade prematurely.
- Whining or groaning noise from the valve body area: Air entrainment from a cracked pipe creates cavitation noise, often accompanied by erratic shift timing.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number (SKU) | 4644.121.242 |
| Material | Steel (zinc-plated) |
| Length (approx.) | 210 mm |
| Outer Diameter | 12 mm |
| Wall Thickness | 1.5 mm |
| Weight | 0.18 kg |
| OEM Reference | ZF 4644.121.242 |
| Sealing Method | Compression fit with O-ring |
Compatibility
This oil pipe is engineered for the ZF WG180 and WG200 transmission families, including all sub-variants such as WG180-1, WG180-2, WG200-1, and WG200-2. It is also compatible with certain ZF Ecomat 4HP and 5HP series that share the same hydraulic architecture. The pipe mounts directly between the TRANSMISSION HOUSING (4644101208) and the HOUSING (4644301333), and it is secured using the GROOVED STUD (0631311009). Always verify the TYPE PLATE (0730365125) on your transmission to confirm model-specific fitment before installation.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644101208 | TRANSMISSION HOUSING | Main structural casing that encloses all rotating components |
| 4644301333 | HOUSING | Secondary housing for valve body and oil channel routing |
| 0730365125 | TYPE PLATE | Identification plate with transmission model and serial number |
| 0631311009 | GROOVED STUD | Fastener for securing oil pipe and housing alignment |
| 0636305019 | SCREW PLUG | Seals oil passages during maintenance or testing |
| 4644301247 | THREADED BUSH | Provides threaded anchor point for housing bolts |
| 0634303485 | O-RING | Seals the oil pipe connection to prevent leakage |
| 4644301257 | ADAPTER | Converts oil port size for alternative pipe routing |
| 0634306023 | O-RING | Secondary seal for adapter or housing interface |
| 4644106231 | SHIFT SYSTEM | Electro-hydraulic control unit for gear selection |
