Overview
The ZF 4644.121.485 OIL PIPE is a critical fluid delivery component engineered specifically for the WG 200 Series transmission. This OEM genuine part ensures precise lubrication and hydraulic pressure flow within the valve body and rotating clutch assemblies. Positioned between the main control unit and the rotating drum, the oil pipe directs ATF to critical friction surfaces, preventing thermal degradation and mechanical wear. The SKU 4644.121.485 is manufactured to ZF’s exacting tolerances, guaranteeing a leak-free seal and consistent oil volume delivery under high-pressure conditions. When installed alongside the 4644101180: TRANSMISSION HOUSING or the 4644301225: TRANSMISSION HOUSING, this oil pipe forms an integral part of the lubrication circuit that protects planetary gear sets from premature failure.
Symptoms of Failure
- ATF puddle beneath the bell housing: A worn or cracked oil pipe allows pressurized fluid to escape, creating visible drips or puddles under the transmission. This is a common symptom when the 4644.121.485 pipe develops stress fractures near the mounting flange.
- Delayed or harsh gear engagement: Insufficient oil flow due to a blocked or deformed pipe causes clutch packs to engage slowly or with a jarring shift. Operators often report a “slip then slam” sensation during 2-3 upshifts.
- Overheating transmission fluid: When the oil pipe fails to deliver adequate lubrication to the torque converter and planetary gears, fluid temperatures rise rapidly. Dashboard warning lights or burnt-smelling ATF are strong indicators of a compromised 4644.121.485.
- Whining or grinding noises from the transmission: Metal-on-metal contact from oil starvation produces a high-pitched whine or low growl, particularly under load. This symptom often escalates quickly if the pipe is not replaced.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 4644.121.485 |
| OEM Reference | ZF 4644.121.485 |
| Material | Seamless drawn steel with zinc-nickel plating |
| Length (overall) | 185 mm ± 0.5 mm |
| Outer Diameter | 12.0 mm |
| Wall Thickness | 1.5 mm |
| Weight | 0.085 kg |
| Sealing Surface | Ground and polished to Ra 0.8 |
| Operating Pressure | Up to 18 bar |
| Temperature Range | -40°C to +150°C |
Compatibility
This oil pipe is primarily designed for the ZF WG 200 Series transmissions, including the WG200, WG210, and WG220 variants. It also fits select WG180 models that share the same hydraulic circuit architecture. The 4644.121.485 is not interchangeable with earlier WG150 or WG160 pipes due to different routing geometries. For proper installation, always verify the transmission serial number and consult the 0730365067: TYPE PLATE to confirm model identification. The pipe mounts directly to the valve body using a 0631311009: GROOVED STUD for secure retention.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644101180 | TRANSMISSION HOUSING | Main structural casing for gear sets |
| 4644301225 | TRANSMISSION HOUSING | Alternative housing variant for WG200 |
| 0730365067 | TYPE PLATE | Identification plate with transmission specs |
| 0631311009 | GROOVED STUD | Fastener for oil pipe mounting |
| 4644301298 | COVER PLATE | Seals the oil pipe access port |
| 0634306525 | O-RING | Hydraulic seal for pipe connections |
| 0636305026 | SCREW PLUG | Closes unused oil passages |
| 4644301279 | SCREEN SHEET | Filter mesh for oil intake |
| 4644301088 | SEALING CAP | Protects open ports during storage |
| 4644106300 | SHIFT SYSTEM | Complete shift actuator assembly |
