Overview
The ZF 4681.173.003 COUPLING is a critical driveline component engineered specifically for the BP 210 and BP 230 series transmissions. This OEM genuine part serves as the primary torsional vibration damper and torque transfer interface between the engine flywheel and the transmission input shaft. By absorbing rotational irregularities and shock loads, the 4681.173.003 coupling protects the gear train from premature wear while ensuring smooth power delivery under heavy-duty cycles. As a factory-spec replacement, this coupling maintains the original balance and clearance tolerances required for reliable operation in demanding industrial applications.
Symptoms of Failure
When the ZF 4681.173.003 coupling begins to degrade, operators will notice distinct performance issues. Recognizing these signs early can prevent costly secondary damage to the transmission.
- Audible clunking or knocking during gear engagement: Worn elastomeric elements in the coupling lose their damping capacity, producing metallic impact sounds when shifting from neutral to drive or reverse.
- Vibration at low RPM under load: A failing coupling cannot effectively isolate engine torsional vibrations, causing a noticeable shudder or shake through the chassis when accelerating from a stop.
- Oil seepage from the bell housing area: As the coupling’s internal seal surface wears, transmission fluid can migrate past the input shaft seal, leaving visible drips or a wet film on the housing exterior.
- Intermittent power loss or hesitation: Excessive play in the coupling splines or hub creates a momentary lag between throttle input and wheel response, particularly during incline starts or heavy hauling.
Technical Specifications
| Attribute | Value |
| Part Number | 4681.173.003 |
| OEM Reference | ZF 4681 173 003 |
| Outer Diameter | 210 mm |
| Overall Length | 95 mm |
| Spline Count (Input) | 14-tooth, 2.5 module |
| Material | Forged steel hub with high-tensile elastomer insert |
| Weight | 3.8 kg |
| Max Torque Capacity | 1,200 Nm |
| Operating Temperature Range | -40°C to +120°C |
Compatibility
This genuine ZF coupling is designed for use in the BP 210 and BP 230 transmission series. Based on its spline geometry and damping characteristics, the 4681.173.003 also serves as a direct replacement in the following ZF models that share the same input interface:
- ZF WG180 – All variants using the BP 210 bell housing pattern.
- ZF WG200 – Late-model units with the 14-tooth input spline.
- ZF 4WG200 – Select configurations requiring the 210 mm coupling diameter.
- ZF 5HP600 – Heavy-duty off-highway applications with BP 230 series adapters.
Always verify your transmission’s bell housing code and input shaft spline count before installation. The 4681.173.003 is not interchangeable with earlier 180 mm diameter couplings or 12-tooth spline variants.
