I have had shake @ 75+ since new and was given the run around about it during my first free oil change and at the 2nd free oil change as well as the 3rd and final. They never even tried for me. I have since installed Toyo tires with balance beads and different wheels. I have a Halo adj. coilover set at 2". Kit came with rear shocks included. The shake is still there with shock and tire changes. I had an alignment when the tires went on and again when the shocks did. I did however speak to someone that mentioned the weight in back of the truck. Said something about "Nervous Chassis" and that may be the issue. I did try out his theory and it did actually help a little. I put 4) 70 lb. sand tubes up against back of cab in bed. Your trying for center of truck and it's this or the back of your cab, you choose lol. I ran like this for a week to avoid placebo effect. I think it is possible it masked the issue, but it did feel like it helped a bit never the less. A truck always runs smoother with a load and in this case it helps a little with the shakes. I needed the room for camping so out came the tubes and since it is rare to catch me going over 65 mph, I left them out. I run a 10 ply and lower the psi to 38-40 to absorb road chatter around town 45 mph and under. Once on the highway this soft tire will distort and cause some good shaking so check air pressure no matter the tire your running to be sure your not causing some shake on top of your shake. Simple I know, but you would be surprised by how many will look at more complicated reasons before the simple things lol. I would like to say I had the answer, but I saw that about weight in bed so I had to say I have heard it too and it helped a little in my case. It's unreasonable to be expected to do this for a smooth ride in a $40k truck even if it solved it completely. 2014 5.3 1500 6 sp 4x4