I hear what sounds like rocks in my hubcap at low speed, especially along the highway barrier. Lately at low speeds the rocks sound goes away and I hear grinding whine, any help would be appreciated, by the way I did check for rocks in the hubcap, none there.

I'd suspect the hub bearings.
I used to load my Dad's hubcaps with a coupla rocks when I was a kid...after a while, he quit taking them out and came up the street dinging along. Still makes me laugh when I think about it.