you need to do more testing---does the vibration appear @ the same rpm or speed---how about going downhill in neutral--if its there all the time , its probably driveline (joints , out of balance ect) . if it is rpm related then i'd look a bad balancer or converter
personally , i'd have the shaft checked for balance , install new joints , and check for u-joint angl phasing
ok so this morning paying close attention on the ride to work i noticed that this vibration is definitely coming from the front, i feel it in the steering wheel and the dash vibrates, i rode with my hand on the center floorboard and did not feel any abnormal vibration coming from the drive shaft. Also noticed this morning whenever i applied the brakes, the dummy brakes light would come on. I just im going to pull the wheels and see if the rotors spin freely or if a bearing is bad, i have no idea what else on the front end would be causing this
Good idea - may as well pack them while your at it anyways....If they look OK then try dropping the d-shaft out and look at the u-joints that way. It can be very tough to tell how good they are when attached. I just went through this with the bro-in-laws truck - looked OK but after it was out the thing flopped around like a fish on one side. It still has a growl we haven't ID'd yet but the vibration went away after new joint.
Even though the tires are balanced they may be out of round. Swap the tires/wheel front to rear and see if it makes any difference.
You check the driveshaft balance by having it checked at a driveshaft shop.