Product Overview The 39Q6-42120 final drive bearing is an angular contact ball bearing used in selected Hyundai excavator travel reduction gearboxes. It is an important internal component of the final drive assembly, supporting rotating gearbox parts under combined radial and axial loads. The related part number 39Q6-42121 is also referenced in aftermarket bearing catalogs. Buyers should verify the exact part number and bearing specifications before selecting a replacement.