Different vibration in driveline after trying everything

Hey all, I'm in a bit of a quandary.

I've had this ultra annoying vibration show up in my truck constantly around 65-75mph, i cant make it go away. If i accelerate it goes away, but as soon as I resume cruising speed, it returns.

I've been trying my damn'dest to kill this vibration.

~Replaced the carrier bearing. (I was able to watch and ensure the driveshaft went back together *Exactly* as before)
~Have had all my u joints inspected
~Religiously lube my u-joints
~Have the tires road force balanced, and aligned several times in the last couple months (3 different shops too)
~Had my wheel bearings checked out and the rear 2 replaced
~Had my axle seals checked out (1 needed replacing)
~checked out tranny and diff fluids


Now heres where it gets fucking wierd.

I decided as one of my few last ditch efforts, was to install a carrier bearing drop bracket (i had a 3 inch lift installed, and diff drop done) (vibration was there before the lift)

So i bought a Carrier Bearing drop bracket from Brian at Street Tacos.

It worked. It reduced the vibrations, but the problem was it made it over a larger MPH spectrum, and I had the dreaded launch shudder.

So i took it off:








Now what? I took off the bracket (only had it on for 3 days), and the launch shudder is gone, but the vibe is still there.

 

Oh, well fuck me then. Guess I'll have to call Brian.

 

well one thing is for sure. you have enough lube in your U-joints lol

 

hey guys i have done some researching and i cant find how to contact brian at street tacos

can you guys give me a website or phone number thanks!