I have a 2000 Silverado 1500 4x4 and I will be replacing the drivers side front hub. The bearing is making some noise and there is alot of rumbling while driving. My largest socket 1 1\4 inch did not fit on the hub nut. Before I go to the store and buy a bunch of sockets can anyone tell me what the size of the nut is?

Thanks

I believe 1 3/8"

A 1 3/8 is about the same as a 35mm socket or you more than like will only find a 36mm which will work. Parts stores will most likely have a 36mm socket.
Otherwise a tool truck or large tool dealer.

I always use a 36mm socket on the axle nut.....