For some reason, my 3rd gear sort of "scratches" when i engage it higher than 3500 RPM, any ideas why?

 

synchro is wearing out. over time it will develop into a full grind. what fluid are you using, and how old is it?

 

No idea how old it is, or what kind of fluid im using. Just started scratching Saturday night, and I only drive it on the freeway to go to school.

 

try changing your fluid....heard good stuf about GM syncros or something...i personally use honda mtf though...might get ride of the the "scratching" but wont solve the problem

 

i had teh same problem with my old LS tranny bfore i got gsr tranny with clutch/flywheel. that's gonna become a full grind in a while unless you make sure you baby it into third now and keep the revs under 3k when doing so.
You should definetely get a tranny flush.

 

It pretty much grinds nwo going into 3rd; hows it gonna get worse?