Need help determining squeak source
 

My 2004 3 s 5spd has a problem that has been bugging me for about a year now. Whenever my car gets hot (such as sitting outside on a hot day) and I have been driving in stop and go traffic for ~15 min starts emitting a loud squeak whenever I am either accelerating from a stop or just after slowing down. It happens both when the clutch is depressed about half-way and not at all. The squeak lasts until about 2 sec after I shift to 2nd. I have taken it to the dealer twice for this problem but both times they can't duplicate the problem.

Any Ideas?