my passenger side front wheel makes a rattling noise while driving. when up on the lift its the only tire that wont spin freely. you spin it and it stops immediately. i figure it was a bad bearing, but they only seel the whole hub assembly. so i went ahead and bought it. is this going to fix my problem? also what size is the axle nut? its HUGE!

 

It very well could be the problem and my money is on it. The only other thing it could be is the brakes rubbing for some reason. Its a good thing to replace it though, you don't want that coming apart while your driving down the road. It can be deadlyl. Alo whats the milage on it? Mine went within 2000 miles of each other just after 100,000 miles. Get ready to replace the other side too

 

it is just about at 135,000 miles. brakes are cool, just turned them.

 

So as long as your caliper isn't hung up then I would agree with the wheel bearing. I usually test wheel bearings by driving in a parking lot and turning the wheels back and forth, if the noise changes than that is usually a wheel bearing. That tip is more useful when you have a growling noise but I thought I would throw it out there.