Can't figure this out!! I will GIVE 50$ to who ever can help me out!!

Your rear drive shaft is 2 pieces. You still had the front half going to the carrier bearing. Yes? No?

 

This is wrong.

Otherwise how would your tires ever get balanced? They spin them to balance them without road forces on most machines still. Tires don't randomly explode when you remove the ground.

 

Agreed.

 

You don't spin your tires at 70 mph to balance them! I doubt tires would explode unless you get them going really fast, but this is still super unsafe to do.

 

Let's not go off subject, thats why I didn't say anything about it lol

The complete rear drive shaft was off during my 4HI road test.

 

Running the truck with your wheels off the ground ( freewheeling )and a hanging suspension changes your drive line angle . You may in fact cause a vibration that you dont normally have . You can try it as a test but it may give you false results .
The vibration should be diagnosed with the truck under load at the speed your vibration occurs
Your torque converter locks up only once the truck warms up . If you are trying to diagnose a TC chatter with the wheels suspended , you wont feel the vibe .
Are you sure your driveshaft is in phase ? any balance weights fallen off ? Is your slip yoke on your driveshaft free to slide ?

 

Bad cv axle?

 

Yeap, just spent 185$ on the rear drive shaft, brought it to the best guys in town. They rebalanced it, U-joints and yoke was good.
I will update once I do the 4 wheels in the air test see what hapends, see if its gives some kind of clue.

 

I'm not gonna read all the answers but I've got the exact problem. It's called the rumble strip problem. It's more common in FJs and someone sells a fix kit. I've also heard it might be the transmission mount bushing. I've learned to live with it and I've got 200k miles since it started

 

I am willing to bet it is ball-joint or tie-rod end related.

Have you checked for play?

 

http://www.levelten.com/mobile/Product.aspx?id=238

 

Thank you for the reply, Im not convinced its from my transmission yet but I will look into this.

 

The t4rs get it too A simple flush may cure it so that's something to look into. I'll be flushing mine in the next couple weeks when I do the rest of my maintenance

 

If you have a GoPro put it under your truck facing the transmission. Your driveshaft will bounce if this is the issue

 

meanwhile check for play in ball-joints and tie-rod ends... lol

 

Not sure what you got going on. But i know its not your needle bearing. I had that issue and it was nothing like what you describe. Plus it would go away in 4wheel high

 

An easy way to check if it's the torque converter is to put it in "4" instead of "d" if you have an automatic. I had the same issue but it was around 45-50 mph when it would change from 4th to 5th gear and i could get it to last a couple of seconds.. Not sure though! Good luck!

 

For sure!

 

If you knew of a local place with a dyno, that could help you eliminate the front end. You could even have a look underneath the truck while the tech has it up to speed. Would also eliminate aerodynamic issues.

 

Driveshaft @Blkvoodoo Just remedied his