Started having some pretty bad vibrations between this mph, started by rotating/balancing the tires and did not help and I was kinda sure it would not as the vibration mostly occurred while foot was on the accelerator let off and it subsided for the most part. Put the truck in N with the brake set to check the drive line u-joint and it did not seem loose but I did notice that one of the rubber seals on one knuckle of the u-joint was starting to peel away, anyone think this could be the issue?

 

Funny you mention this problem, I had the same issue just last week. After further research it turned out to be my furthest rear u joint going bad. My symptoms were extremely annoying vibrations from the speeds of 55-69 mph and a clicking noise between 57-61 mph. I found myself driving around with my windows down to deaden the cab noise. Lot of good information and help here on FTE. I am a new out the box shade tree mechanic and this site makes it work. New Spicer 5-160x's, vice, BFH and a little patience did the trick. Now I can drive around windows up and hear my tunes.

 

U joint or as what happened to me was some bolts started coming loose on my driveline

 

Yup exactly what was going on, u-joint was bad, rear one but I strayed from the BFH in this case and I took it in to my local trusted diesel shop. Once the pulled the drive line I found out that the female end of the spline was also missing a plug of some sort and filled with dirt and other debris, must have been a P.O. bull****ing deal.. So the drive line got sent out to the local machine shop, found to be .040 out and it got trued up zerod out and I replaced all the u-joints just on principle. No vibration at all now, even the vibs I attributed to worn/out of balance tires are gone, so stoaked on that.

Also, if any readers 'remember my last thread recent thread about lack of boost and not being able to get over 15lbs. they were able to replace my EBPV Sensor as I had always gotten p0475 code I believe, as well as cleaning the tube which they said was pretty caked, and now I can get boost needle all the way to 24 just accelerating, no load, normal driving conditions. So happy about that, not turbo surge after all. The needle does still flutter right at 15lbs still so I assume i have a small boost leak somewhere I will have to trace down.