No, I am not an auto tech type, so can't DIY. I do understand a lot of this stuff though, have an engineering background.

So your response is that this kind of an islated thud COULD be due to ball joint, control arm bushing, or strut mount as well. THen how can find out the culprit - can the tech do it by a visual inspection, or does he just have to guess and keep changing parts till it gets fixed? Are there any tests that he can run?

Thanks again. I am hesitant to take it to the dealer due to past bad experiences - he will charge me 150 bucks for "disgnostics", and then say it need 20 new components, give me another 1500 bucks, but I don't guarantee that the noise will go away. Has happened to me before.

Can I crawl under the car and check the components myself a little bit? If yes, can you be so kind as to tell me how?