velocipedio is right. Aluminum has very different properties than steel and sometimes gives you problems.

In my case, the head mechanic at a very good bike shop in the area had attempted to put some loc-tite into the frame from the BB. He said most of the time you can cure the frame from clicking if you did this. But, there has to be a hole through the BB into the frame's innards to squirt the loc-tite through. My TREK didn't have the hole so they couldn't perform the loc-tite magic.

Since it was under warranty they shipped it to Wisconsin and it got replaced. If you have a warranty, work it. If not, maybe a tube of loc-tite isn't such a bad idea...

Anybody ever try this? Did it work?