My dad has a 2004 2500 4x4 quad cab short box 48re. Stock other than muffler and an s&b intake. Well soon as you hit the throttle it starts to vibrate. let off goes away. I checked u joints and the drive shaft...any ideas. It's pretty bad.
Thanks

 

does the truck have any other symptoms? loss of power? tranny issues?

 

Is the vibration from the front,back,middle?

 

you could also check the torsion damper

 

Check the Driveshaft..
Had pretty close to the same issues your having, ended up being the rear U-joint on the drive shaft was half frozen