Overview
The ZF 4681.371.013 IDLER is a precision-machined component engineered for the BP 210 and BP 230 series of industrial transmissions. This genuine OEM part functions as a critical load-bearing element within the gear train, distributing rotational force between the input and output shafts while maintaining correct gear mesh alignment. Without a properly functioning idler, the transmission’s gear synchronization degrades, leading to uneven wear across the entire drivetrain. The SKU 4681.371.013 is manufactured to ZF’s exacting tolerances, ensuring minimal backlash and consistent torque transfer under heavy-duty operating conditions.
Symptoms of Failure
When the ZF 4681.371.013 IDLER begins to fail, operators may notice distinct operational issues. Identifying these signs early prevents costly secondary damage.
- Whining or grinding noise during gear engagement: A worn idler bearing or tooth surface creates a high-pitched metallic sound, especially noticeable when shifting between forward and reverse in BP 210 series units.
- Intermittent gear slippage under load: As the idler loses its dimensional integrity, the gear train loses proper mesh, causing the transmission to momentarily slip when climbing grades or moving heavy loads.
- Metallic debris in transmission fluid: Flaking or pitting on the idler’s hardened steel surface contaminates the oil, visible as glittering particles during routine fluid changes.
- Vibration at specific RPM ranges: An unbalanced or worn idler induces harmonic vibrations that resonate through the transmission housing, typically between 1,200 and 1,800 RPM in BP 230 series applications.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number (OEM) | 4681.371.013 |
| Material | Case-hardened alloy steel (20MnCr5 equivalent) |
| Outer Diameter | 92.0 mm |
| Inner Bore Diameter | 30.0 mm |
| Overall Width | 28.5 mm |
| Tooth Count | 23 (helical profile) |
| Weight | 0.85 kg |
| Surface Hardness | HRC 58-62 |
| OEM Reference | ZF 4681.371.013 (Genuine) |
Compatibility
This genuine idler gear is designed for direct integration into specific ZF transmission families. It is a direct fit for the BP 210 Series and BP 230 Series industrial transmissions. Based on its dimensional profile and tooth geometry, the 4681.371.013 is also compatible with the following ZF models when used in auxiliary drive positions:
- ZF WG180 (secondary idler position)
- ZF WG200 (counter-shaft idler)
- ZF WG210 (main idler gear)
- ZF 4WG-200 (torque converter idler)
Always verify the existing part’s tooth count and bore diameter before replacement. For models outside the BP series, consult your ZF service manual to confirm interchangeability.
