[VinceY]

My C/10 has a vibration 55-60 and 75-80.
Can't remember exactly what my mechanic said was wrong with the drive line there but he told me how to fix it.
2 options:
1. Don't drive those speeds and if you do
2. Turn up the stereo.
It is a very minor vibration so hours of trying to find it will just cost too much and drive you crazy.
Minor enough that a couple of weeks ago I was under my truck and found a lug nut that was just sitting on the frame. That lug nut had sat there since approx. 1998 and about 7000 miles.