Overview
The ZF 4644.305.021 OIL FEEDING RING is a precision-engineered component designed for the WG 200 series transmission. This OEM genuine part sits directly within the rotating clutch drum assembly, where it meters and directs hydraulic fluid to the clutch packs and lubrication circuits. Without this ring, the transmission cannot maintain proper oil pressure or flow. The SKU 4644.305.021 is the exact replacement for the original factory-installed part, ensuring a perfect seal and consistent oil delivery under high-torque conditions.
Symptoms of Failure
- Oil leaks around the clutch housing — A worn or cracked feeding ring allows pressurized ATF to escape, leaving visible puddles under the vehicle or transmission.
- Gear slipping during acceleration — Insufficient oil pressure to the clutches causes delayed engagement or complete loss of drive in specific gears.
- Erratic shift quality — Hard or soft shifts occur when the ring fails to regulate oil flow, leading to harsh engagement or flaring between ratios.
- Overheating transmission fluid — Reduced lubrication flow from a degraded ring accelerates wear on bearings and clutches, raising operating temperatures.
Technical Specifications
| Specification | Value |
|---|---|
| Part Number | 4644.305.021 |
| Material | Hardened steel with nitrile coating |
| Outer Diameter | 145 mm (estimated) |
| Inner Diameter | 120 mm (estimated) |
| Thickness | 8 mm (estimated) |
| Weight | 0.35 kg |
| OEM Reference | ZF 4644.305.021 |
Compatibility
This oil feeding ring is primarily used in the ZF WG200 series, including models such as WG180, WG200, and WG210. It is also compatible with certain variants of the WG150 and WG250 where the clutch drum assembly shares identical oil gallery dimensions. Always verify your transmission serial number before ordering.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644105417 | DISCONNECTION | Separates clutch packs during shift events |
| 4644303547 | OUTPUT FLANGE | Connects transmission to driveshaft |
| 4644303012 | OUTPUT FLANGE | Alternate output flange for different yoke sizes |
| 4644101121 | TRANSMISSION HOUSING | Main structural casing for gear train |
| 4644301240 | TRANSMISSION HOUSING | Rear housing section for WG200 series |
| 0730365067 | TYPE PLATE | Identification plate with transmission specs |
| 0631311009 | GROOVED STUD | Fastener for securing oil passages |
| 4644301286 | COVER PLATE | Protects clutch drum from debris |
| 4644301242 | COVER SHEET | Thin gasket for sealing cover plate |
| 0636101026 | CAP SCREW | High-torque bolt for housing assembly |
