shutter around 20 to 40mph need help!

i have a 2007 double cab short bed with a very small lift on it with addaleaf and leveling kit when i start from a stop and i get to 20 to 40mph i get a shutter that if i let off or throttle on it stops i have been told it is my lift, my cerrier bearing, and my tires i need help thanks

 

u-joint angles

shudder

 

so if i shimmed the drive shaft down would that fix the shudder?

 

you want to shim it upward, tilting the front of the pinion yoke slightly up.

 

You want the two halves of your driveline to be parallel and the u-joints at the t-case and pinion to be equal angles.

Theres a whole thread on this.

 

i have had the tires all balanced i need new ones they are cupping and one mechanic told me that is what the problem was but I'm not sure on that

 

how would i go about doing that

 

theres a thread somewhere???