Funnyboyd

I recently had my mechanic replace my clutch, after the pilot bearing failed. They used the "transmission fluid recommended by the dealer." Now I have a slight crunch when I shift into 3rd, and a pronounced one when shifting into 4th. If I baby it when shifting, I avoid the gears crunching, or if I shift at lower RPM's. This seems too coincidental to be synchros going bad, as it happened as soon as the new clutch was in. My mechanic is an independent, seems to be knowledgeable about RX-8's, but didn't know why this might occur unless it's the fluid used. Can the fluid make a difference? If so, is their one that anyone might recommend? Any other recommendations? Thanks!

I have a 2005 Shinka edition, with 160K miles.