I feel the clunking (no clicking) below my feet (feels like somewhere underneath the car).

clunking noises around bumps, clunking noise if I jerk the steering wheel left and right fast, some vibrations 65mph and up.

Mechanic checked joints, sway bar + links, shocks, tie rods, wheel bearing... couldn't find the problem.

I starting to think it's the steering rack?

 

Is there any play or looseness to the steering when you turn the wheel with the car off? Any knocking noises when you turn the wheel in the other direction?

I see that the mechanic checked the joints, but double check the upper ball joint. Just reach in and try to move the arm up and down. Maybe the lower control arm rear most bushing?

 

Are the CV Axles worn out? Check them out or have them checked.

 

whats ur suspension combination?