I have a 2003 WRX with 118,000 miles on it. I am the original owner and it has the original clutch. I drive the car harder than I would a minivan, but I am never abusive, especially when it comes to hard launches, shifting, etc. Very few mods, mechanically well maintained. I do a fair job matching RPMs when shifting, just out of habit driving old trucks, etc. I started noticing a sort of shh sound primarily in 5th gear. Not very loud (I actually can't remember when it started), but it is beginning to nag at me. It is loudest when I am not touching anything and the shifter is resting on the left side of the fifth gear gate. If I move it to the center or right of the gate, the sound all but goes away. I can also replicate the sound in fourth and third (and possible 1 & 2- hard to hear though) by pushing the lever lightly away from its center position (I know its bad to drive around with your hand on the shifter, I am just doing this for a moment to attempt to diagnose the problem). I am leaning towards synchro noise, but it shifts perfect; no grinding at all. Could it be the linkage is out of adjustment? Performance has not changed. I don't even experience the issue shifting into 1st as long as the car is going under 15 or so (it is actually slightly better than when I bought it). I recently changed the tranny fluid again (new AMSOil 75W90), but that made no difference at all.
Is this something I should worry about, or just turn on the radio? I tend to fixate on car noises...