"screeching" when shifting, help!

[02nbmvert]

Hey guys, i'll start off by apologizing if i'm posting this in the wrong area. since i have NO IDEA what the problem is, i also dont know where to look for help. i noticed yesterday that under hard accelleration (especially through the 3-4 shift) my car seems to have started making a screeching or squealing noise for about half a second right before it shifts when the rpms get up to the orange. its an A4 by the way. also it seems as if my "piston slap" has become slightly worse(noticed both at the same time), although maybe i'm just looking too much into it since noticing this other noise. the ONLY thing i've done to the car recently is complete seafoam and change oil, along with other aspects of a tune up (change plugs, FRA mod, air filter,etc.) so i doubt that this could have been caused by anything i've done. please help!

[anniversary30]

First thing I would suggest is change your belt if you havent already.

[02nbmvert]

awesome, thanks man... i totally overlooked that... also now that you mention that, when i used the seafoam deep creep on the TB a fair amount leaked out and was dripping everywhere, i cleaned up what i could but maybe that could be contributing??? i'm just worried its something expensive, because i dont have money to fix something expensive and thats how my luck has been going lately!:faint: there also seems to be some kind of very slight knocking noise when the cars on and in gear (doesnt do it when its in park though)... *sigh* i need a good mechanic! and a wealth of knowledge! thanks!