I'm towing a 4000lb travel trailer with a weight distribution hitch. I've got a vibration that appears at 30 mph and at 70mph. I've lifted and spun all trailer tires and found one to have a bit of brake drag. I'd just the tires to be questionable due to sidewall cracks. The truck doesn't exhibit the vibration unless the trailer is being towed. Before I plunk down $500 for tires, has anyone dealt with harmonic vibration issues in our trucks? Have heard of this even with Ford F350s.
