[Gee]

Not enough info on, but assuming that the nut is stripped. If you have a file or dremel you can flatten two sides so you can get a smaller wrench on it. If it in a deep pocket of a wheel like a velocity six rim. You can try a slightly smaller socket and place it on a driver and tap it onto the nut.

If the nut isn't stripped and the axle isn't turning then it sound like the stub axle has broken off. Need to find a way to get a hold of that stub axles while you are turning the nut.

Then again if you are putting your true track on it. May as well just remove the arms and drive shaft all in one swoop and that should give you a better view of the problem. That way you can tell us a little more then it just to tight.

Good Luck.

Thanks for the link what's_nitro