[abc816816]

Long story short, My car has rattling noise in front suspension when the wheels go over speed bumps even slowly, there are no noises when I turn or take corners. I searched some threads and realized that this should be because the front sway bar endlink was loose, and the top nut need to be retightened. My dealer quoted me $146.8 diagnose fee to look this issue even though my car is still under factory warranty. Is this reasonable, or they just want to rip me off?

Thanks