How do I check if my YIKONG YK8081 RC Car Drive Cups are worn?

To check the YIKONG YK8081 RC Car Parts Drive Cups (80039) , remove the driveshaft and inspect the pin holes for elongation or rounding. Insert the drive pin and check for excessive play. If the pin wobbles significantly or the hole has become oval, the cup needs replacement. This is a key part of regular maintenance on the YK8081's high-power 4WD system.