I bought a 2007 Ram 1500 sport back in Oct. 2011. Love the truck, but has a bad vibration in the rear at high speeds (95 kms and up). All tires are worn about half and are scalloped. I noticed in the rearview mirror that the box is bouncing up and down bad on the drivers side. I replaced the back left tire and had it balanced and installed. Vibration is still there. Any ideas?

 

Welcome Aboard Again jackrabbits24!

 

Welcome to DF
Could be bad U-joints, a weight fell off the drive shaft or a loose nut on the rear pinion flange?