I have an annoying vibration 70mph and above . Here is what I have done so far: Swapped tires, balanced drive shaft, changed transmission tail shaft, it did it with the stock 3.27 gears, 3.73 gears and now with the 4.10s always does above 70mph RPM does not matter. All bearings in the rearend have been changed. Checked the pinion angle, Does it in or out of overdrive. Front brakes are new. I changed both upper and lower control arms. did it with lowering springs and now drag springs, did it with stock struts and shocks, have since changed. I have an appointment Monday to get the alignment done if that doesn't fix it I am running out of options. Looking for other suggestions.

 

Stupid question but u didn't say anything about balancing the actual tires. But I'm not even gonna say that cuz I'm sure u tried that already. Are the tires "flush" against ur rotors? Lift the car and see if you can wiggle the tires to see if they are loose

 

I have tried two seperate sets of wheels and had the wheels off and on several times with no change. I am getting a new set of wheels tomorrow I will double check the rotors and make sure the wheels are all sitting flush