I just recently purchased a 2017 Grand caravan SXT I have a vibration in the rear end I've changed two new tires rear shocks had the tires checked and balanced four times rotors check calipers check brakes checked and nothing is taken care of my vibration any tips or comments will be appreciated mechanics have gone front-to-back nothing is broke bent or loose vibration starts at 65 75 on expressway

 

Welcome to DF! Moving this to the caravan section for ya.

 

Perhaps a wheel bearing starting to go bad ? I seen sometimes wheel bearing will start vibrating before they go real bad and start howling.

 

may want to check all suspension bushings. make sure to check on the ground or on a frt end machine rack up in the air would be easiest. the reason i recommend to check on grd or frt end machine is that when suspension is hanging the components are not in a relaxed neutral position and can take play away. there should be some play but not sloppy play.