Knocking sound

SOHEIL SARBAZIAN

MEMBER
2003 CHRYSLER 300
150,000 MILES

Hi, a month a go I replaced the rear struts, front lower control arms, and front stabilizer and their bushings.Then I took the car for an alignment and two days after that, I started hearing a sound under my legs from under the car when hitting the bumps especially when turning left and one of my wheels hits a bump. the sound also sometimes gets repetitive when going on an uneven or a bit bumpy road and it feels as if someone is hitting the car from beneath with a hammer. So I went to the mechanic and he said it could be the sway bar bushings, so I replaced them but the sound is still there, then he said it could be the front struts, so I replaced them too but still nothing, then he said it could be the inner CV axles of the driveshaft, so I replaced both driveshafts and their axles but still nothing. His last guess is the output bearing of the transmission to the inner CV axle. But I cannot trust him anymore after all this. Please help me find out
what could be the problem. Thanks
Here I made a video of the sound :
https://youtu.be/99yQ9TBHnbM

1 Reply

CARADIODOC

MECHANIC
33,744 POSTS

If I have not lost faith in your mechanic yet, the half shafts would have done it. I have never heard a thumping or clunking noise caused by them.

You did not mention the most common suspect. Those are the outer anti-sway-bar links. To identify them as the cause, reach over the top of a front tire and wrap your fingertips around the link. It runs up and down right alongside the strut, and is attached to the strut very near the top of the tire. Use your arm to raise the car and let it drop. You only need to bounce the car a half inch or so. The wheels need to be straight ahead. If that link is worn and sloppy, you will feel the knocking as you bounce the car.

The inner anti-sway-bar bushings were good suspects too, but to verify that before replacing them, hold your finger on the bar, right next to the rubber bushing, (with the side of your finger touching the bushing). Bounce the car up and down an inch or two. If the bushing is worn, you'll feel the bar bouncing within the bushing. You should feel no up and down movement.