1406 4 pole 4600kv

[kingdomracer]

I've experienced this where a hub pin is broken and you can't see it until you take the hubs off.
Come to think of it make sure your center drive shaft is working with both front and rear hubs attached properly to the center diff/slipper clutch and the front diff too.
Once a set screw was able to back out and not until I took it apart I didn't see it.