vibration feeling/sound

[01thunder]

reaching 80 mph, vibration is felt, humming vibration sound heard, sound coming from rear. thoughts for repair? diff, driveshaft, Ujoints?

 

[01thunder]

anyone? suggestions?

 

[absalom]

If your question wasn't phrased like the intro to a popular Cake song, you might get more hits.

What have you recently done to the truck? We need a lot more info.

 

[01thunder]

haven't done anything. around 70 it's ok. once speed starts to rise toward 80, the vibration starts and i feel it in the seat. past 80, it is still felt/heard but not as much. U joints are sound/tight. i don't know anything about these diffs to know if it is going bad.