intermittent rear vibration at 60mph

[SilverBullet75]

If you are lifted too high, you will get that grinding. I was using OME 919s plus DAYSTAR spacers and it was really bad. Removed the spacers and it was manageable by greasing the driveshaft. Try greasing first. It helps.

[VXorado]

Try greasing first. It helps.

+1, I was getting a grinding noise from the driveshaft u joints until I started greasing them regularly. I would only get the vibration/noise at highway speed, so it seems to fit the problem.

[Y33TREKker]

...greasing the driveshaft. Try greasing first. It helps.

X2