dirtjumper250

I had a simular condition. I had a vibration that started around 60mph. I checked all the normals, tires, balance, rotors, drums,wheels, and axles. I could not find the problem. I even pulled drive shaft out checked joint and looked to see if it looked bent or off. all looked good. But I went ahead and ordered a new alumnim drive shaft from ford motor sports and installed it because I drag race and wanted a lighter shaft. Low and behold the vibration was gone completly. I guess the old drive shaft was twisted but not bad enough to see with the naked eye. Hope this helps.

a_penquin

dirt beat me to it, sounded like the driveshaft was out of balance.

bbbngowc

Dirt's vibration started at 60MPH. Mine kicks in around 35mph, lasts until about 45mph then vanishes. Reappears when breaking.