I have a 2005 dodge ram 1500. When accelerating at speeds of 45-65 there is a slight vibration which seems to be coming from the rear or center of the truck. The vibration stops when I let go of the gas or go slower then 45. I was thinking maybe ujoints but was unsure. I did have a bad pinion seal on the dif which I replaced already.

 

 

I second the u-joint. Only way to tell is to check them for play.

 

Ujoints where definitely the problem. Thanks!