Reviving this thread to say that the drivetrain vibrations are surprising in my truck as well. If I look anywhere at the interior of the truck through the rearview mirror, I can see it all vibrating and buzzing if I'm going any more than 40mph. You hear it too.
Also there is a very distinct change in noise and feel as soon as I cross over exactly 50 mph. The cabin suddenly gets several dB louder, like a switch is flipped. It's just a hum noise. Sometimes it suddenly dissappears as well, and it gets much quieter and more comfortable inside.
I think I measured (if I remember correctly) about 90 dB inside the truck cruising at 75 mph. I'm sure some of this is my cracked head gaskets but man it's loud.