I just picked up a 90 Integra LS and the trans seems to be making a weird noise. In 1st-3rd if you are decelerating or downshifting it seems to make a grinding/scraping noise. Anyone have any thoughts on what this might be?

 

check your transmission fluid level. If it's a winding-down sound with a slight sand-paper-on-wood sound, it could very well be the lash in the gears and it's nothing to be worried about.

 

It sounds like a bearing issue...but as garados said, be sure to check the fluid level on the side of the trans...17 mm plug I believe. Good luck!