I have a 97 G Caravan with vibration at 60 mph and up - not through the steering wheel, but through the body of the van. Tire rotation makes no difference. One rear wheel has about 1/8" play top to bottom and left to right, the other is tight. I assume these wheel bearing/hub assemblies should be without any play whatsoever. Is this correct, and can this amout of play cause the vibration? thks.