What can cause your truck to make a loud thumping noise every time you make a left turn or go over a bump?

-I have a 99 chevy tahoe and was recently in a car accident and had to have the front fender on the drivers side replaced ever since the accident ive been hearing a loud thumping like noise every time i make a left turn or go over a bump what could be causing this noise? Toke it to a repair shop they told me nothing was wrong with it my dad is the one that put the front fender on the truck. Any answers will be greatly appreciated.I would suggest that you return it to the shop that did the work and get them to fix the problem.
Check the shock absorbers.