Love the forum guys - just found it. I have a 02 325xi and lately when I am cruising between 60-70mph and then accelerate it makes a grinding noise like a thud (hard to explain) but of course does not do it all the time. It just does it between those speeds and not at any other point or getting up to that speed. It is kinda loud sometimes and then other times you can't hear at all. Haven't taken it to my dealer yet - I am sure when I go I will not be able to reproduce it. Sounds like Homer Simpson - doh! Any ideas?