Driveshaft problems Part 2

[TeamTorqueJuggernaut]

Ok, I have gone through 3 different driveshafts. One was even a one piece that I had custom made, but Im still have vibrations. I've had the tires rotated and balanced so I know thats not the problem. Could it be the rear end causing the vibrations? I've gone throught seven seals and almost ran the transmission out of gear oil a couple of times. Im getting tired of it and I dont want to cause any damage to the transmission. I also have a sr swap just to give yall a little more info about the car. I really need some help on this.

[Goldeneagle]

Have the driveshaft balanced. If you have not done so already.