I have a vibration mostly when empty between 60-70 mph
Not so noticeable when loaded. When empty if I coast it mostly goes away. But under power i can feel it in my feet and the seat.
Tool the driveshaft off between the diffs. Run it up to 65mph and was still there. So unhooked the shaft between the front diff and the carrier bearing and it was gone. So on another not I noticed the the yokes on the first driveshaft were not in phase. The one by the carrier bearing was phased 90*. Also noticed when i ran the truck with the short shaft unhooked the front diff made quite abit of noise. wondering if the vibration could be coming from it?