Overview
The ZF 4644.303.087 OUTPUT FLANGE is a critical driveline component engineered specifically for the WG 181 series transmission. This OEM genuine part serves as the mechanical interface between the transmission output shaft and the propeller shaft, transferring rotational torque from the gearbox to the vehicle’s drivetrain. Machined from high-strength forged steel, the flange ensures precise alignment and vibration-free power delivery under heavy load conditions. The SKU 4644.303.087 is a direct replacement for worn or damaged flanges, restoring factory-spec performance and eliminating driveline play. When paired with a properly sealed TRANSMISSION HOUSING, this output flange maintains oil containment and bearing preload integrity throughout the assembly.
Symptoms of Failure
- Transmission fluid seepage at the output shaft seal — A worn flange surface or damaged spline contact area allows oil to bypass the seal, leaving visible drips under the bell housing.
- Driveline vibration during acceleration — Eroded flange bolt holes or a warped mating face cause rotational imbalance, felt as a low-frequency shudder through the chassis.
- Clunking noise on gear engagement — Excessive spline wear between the flange and output shaft creates backlash, producing a metallic knock when shifting from neutral to drive.
- Premature bearing failure in the transmission housing — A loose or distorted output flange misaligns the output shaft, accelerating wear on the HOUSING bearings and requiring costly rebuilds.
Technical Specifications
| Parameter | Specification |
|---|---|
| Part Number | 4644.303.087 |
| Material | Forged alloy steel, induction-hardened |
| Overall Diameter | 165 mm (6.50 in) |
| Pilot Bore Diameter | 45 mm (1.77 in) |
| Bolt Circle Diameter | 130 mm (5.12 in) — 6 holes |
| Spline Count | 14 involute splines |
| Weight | 2.8 kg (6.2 lbs) |
| OEM Reference | ZF 4644.303.087 |
| Surface Finish | Black oxide corrosion protection |
Compatibility
This output flange is a direct fit for the ZF WG 181 series transmission, commonly used in medium-duty trucks, buses, and off-highway equipment. It is also compatible with the closely related WG 180 and WG 200 series gearboxes, as these share the same output shaft spline geometry and bolt pattern. For applications requiring a replacement THREADED BUSH or updated TYPE PLATE, verify the transmission serial number against ZF service documentation to ensure correct assembly.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644101047 | TRANSMISSION HOUSING | Main structural casing supporting all internal components |
| 4644301380 | HOUSING | Rear bearing carrier and seal bore for output shaft |
| 4644301189 | THREADED BUSH | Wear insert for flange bolt threads in housing |
| 0730365067 | TYPE PLATE | Identification tag with transmission model and serial |
| 0631311009 | GROOVED STUD | Alignment dowel for flange-to-housing positioning |
| 4644301161 | COVER PLATE | Protective shield over output shaft access port |
| 0636100621 | HEXAGON SCREW | M12 fastener for securing flange to output shaft |
| 0631610020 | SET SCREW | Locking screw for threaded bush retention |
| 0634801098 | SEALING RING | O-ring preventing oil migration past flange |
| 4644301117 | FIXING PLATE | Anti-rotation bracket for output shaft nut |
