The truck vibrates violently . 4x4 problem

Does the vehicle make any noises while driving? If there is a "growling or roaring " noise associated with the vibration, check the right front hub bearing. If there are no noises and only vibration, check the right front upper ball joint and control arm bushings. The Trailblazer's upper ball joint and control arm bushings become worn and cause the tire and wheel assembly to shimmy while driving. The vibration stops when turning left because of weight transfer to the right side which keeps the wheel steady for a moment. Also, check the tire for irregular wear.

Warped rotors or out of balance tires can cause this. Have you had a front-end alignment after putting these steering/suspension parts on? When replacing these parts IT IS CRITICAL TO HAVE ALIGNED. Also, Have you checked condition of front HUB/WHEEL BEARINGS?

When you put the vehicle in drive with your foot on the brake, and you hear a clunk. You may have a bad CV joint or axle. If not it may be a bad wheel bearing. Those would be the first two I'd Check. Outside of that sometimes poor wheel balancing or a tire belt separation. Either way it should be looked at before you hit 75+ mph. I had a Honda that I had just got off the highway with my wife and 3 month old daughter in the car. On a side street pulling away from a stop sign. The right CV shaft let go and dropped the wheel on the ground. There wasn't as much as a shimmy or a groan prior to that. If we had stayed on the highway another five minutes, I can only imagine. Please check it out for your own safety.

Have the wheel bearings / wheel balance checked.

Did you lock the front hubs?

does it lock down the tire or just try and shake the wheel out of your hands? if it is a violent vibration it is most likely the axle

you probably have a problem with the differential in the front it might be no good it looks like a rear end pull the cover off and check the gears

chances are your shocks are worn out completely. replace the shocks with a good quality set and take it for a drive. cheers.

Look over tires for blistering or bubbles.
Check front end for any loose components.
Warped rotors will also cause vibration. check rotors first. A shop can test the rotors for you.

This could be a number of problems. I just had the exact same problem and they told me that my 4x4 driveshaft was kicking into auto over and over again. Had to take it off and it was fixed, but it led to front end issues. ( Front End binding and locking up in turns)