Overview
The ZF 4681.173.002 COUPLING is a critical driveline component engineered specifically for the BP 210 and BP 230 series transmissions. This OEM genuine part functions as a torsional vibration damper and mechanical link between the engine output and the transmission input shaft. By absorbing rotational irregularities and shock loads, it protects the gearset from premature wear while ensuring smooth power transfer. The SKU 4681.173.002 is manufactured to ZF’s original factory tolerances, guaranteeing a direct fit and long service life in heavy-duty industrial applications.
Symptoms of Failure
When the ZF 4681.173.002 coupling begins to degrade, operators will notice distinct operational issues. Recognizing these signs early can prevent costly secondary damage.
- Audible clunking or knocking during gear engagement: Worn elastomeric elements within the coupling create excessive backlash, producing a metallic noise when shifting between forward and reverse.
- Increased driveline vibration at low RPM: A failing coupling loses its ability to dampen torsional harmonics, causing noticeable shaking through the chassis, particularly under load.
- Oil seepage around the bell housing area: Deterioration of the coupling’s internal seal can allow transmission fluid to escape, often mistaken for a main shaft seal leak.
- Erratic power delivery or “shuddering” during acceleration: As the coupling material hardens or cracks, it fails to transmit torque smoothly, resulting in a jerky or surging sensation.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number / SKU | 4681.173.002 |
| Outer Diameter | 210 mm (approx.) |
| Inner Spline Diameter | 38 mm (approx.) |
| Overall Length | 95 mm |
| Material | High-tensile steel hub with nitrile rubber element |
| Weight | 2.8 kg (6.2 lbs) |
| OEM Reference | ZF 4681.173.002 (Genuine) |
Compatibility
This coupling is designed for the ZF BP 210 and BP 230 series transmissions. Based on its spline configuration and damping characteristics, it is also compatible with the following ZF marine and industrial gearbox models that share the same input coupling architecture:
- ZF WG 180 (early production runs)
- ZF WG 200 (with SAE 3 bell housing)
- ZF IRM 220 (reversing reduction models)
- ZF 220A (select variants)
Always verify the spline count and pilot bore dimensions against your existing unit before installation. For exact fitment confirmation, cross-reference the 4681.173.002 with your transmission’s serial number.
