Every so often there is sudden noise,more like a loud, dull thud. It happened about three times so far, about a week apart. I haven't heard it for about two weeks now. I will be driving along on a smooth, straight street and it happens. It's like someone banged on the side of the car. I can't tell where it is coming from. I know it isn't from the suspension. Sounds like it is coming from the passenger side, maybe from under the car or in the fender well on the passenger side. It only happens when I am driving. There is nothing I can see or feel. Anyone have any ideas?

 

I would check the engine mounts.

 

+1 on checking mounts...also I recall reading a thread regarding a broken trans brace/cross member....but it only happened under acceleration. Now I'm not saying this is it, but just review this thread, I state where I had a clunk which help lead me to my issue... https://www.jaguarforums.com/forum/x...g-info-188400/

These cars are at the point where items like these can happen, ..age gets to us all.

 

I had a loud thump on occasion and felt as though there was something that was pulled the car backwards then letting go. I found the pins that hold the parking brake shoes to the back-plate had pulled through, they were getting trapped between the shoes and brake disc. I ended up getting new back-plates, pins, and discs as it had chewed up the inside one of the discs? It's a 'shot in the dark' but that's what happened to me? It's one of those issues that can be difficult to trace!
Paul

 

Thanks for all the replies. I now have a starting point.